MAR-193: Fix deprecation warnings coming from newer versions of pip-tools:

- In more recent versions of pip-tools, a new option has been
added (--strip-extras) that will become a new default in next major
release. Not using this option causes some warnings on Debian 11
Bullseye when pip-tools is brought up to date.
- Refactor the invocation of pip-compile to make it more modular.
- No test expansion for this since it would make it a bit harder to
target both Debian 10 Buster and Debian 11 Bullseye.

MAR-193: Updated requirements file for up-to-date version of Python:

- Primarily required in order to run Gimmecert in tests.

MAR-189: Disable use of KVM paravirtualisation provider with Vagrant/VirtualBox:

- The VMs seem to randomly hang when the (KVM) clock source gets
initialised right after getting past the bootloader. Helps run the
tests in a way more reliable way.
- Should be removed if upgrading to latest kernel/VirtualBox versions
helps.

MAR-189: Replace The Bug Genie deployment as part of usage instructions with Nextcloud:

- Nextcloud is still being properly maintained, and should be way less
hacky to roll-out as opposed to TBG.

MAR-189: Drop development upgrade instructions for Molecule/Testinfra:

- This has been done long time ago, and it's just a leftover artifact
at this point (has no real value any longer).

MAR-189: Drop the deprecaetd/unknown mutt options for test site:

- No longer works at least with mutt version coming with Debuan 10
Buster.

MAR-189: Updated instructions and configuration for test site for Debian 11 Buster:

- Use a more generic Emacs package name.

MAR-189: Rework fix for legacy iptables and ferm:

- Unfortunately, using diversions with iptables legacy binaries does
not work correctly because the iptables package will try to run
update-alternatives on install/upgrade, and error out because the
files are not available in the original locations.
- Divert the ferm binary instead, and roll-out a custom patched
version of it instead.
- Use a custom script to drop the legacy iptables (for both IPv4 and
IPv6).
- Update the tests accordingly.

MAR-189: Refactor test for additional SMTP server configuration:

- Use different override to avoid Postfix warnings about overridden
configuration option in the same file.

MAR-189: Added support for Debian 11 Bullseye to mail_server role:

- Shorten the backup client username so it would be under 32
characters.
- Switch all helper VMs to using the Debian 11 Bullseye as well.
- Drop the architecture suffix from hostnames.
- Update the hostname for client VMs.
- Fix the incorrect format for the message ID used in various mail
delivery tests.

MAR-189: Merge some configuration changes from Debian Bullseye for mail server configuration files:

- Get rid of using the session cache databases for TLS for smtpd -
this is no longer the preferred way to handle it (RFC 5077 TLS
session tickets should be used).
- Indicate that the delivery through external commands is final (X
flag of the pipe(8) mechanism). Affects the delivery status
notifications, changing them from "relayed" to "delivered".

MAR-189: Added support for Debian 11 Bullseye to xmpp_server role:

- Roll-out LDAP client configuration since Bullseye does not come with
a stock one at /etc/ldap/ldap.conf that sets the trust anchor
correctly for validating LDAP server certificates.
- Drop the backports pinning in case of Bullseye (for now let's try to
keep the Buster and Bullseye at same versions for simplicity).
- Drop installation of Python apt bindings (no longer used).
- Tests for Buster and Bullseye need to be split-up a bit due to some
differences around backports etc.

MAR-189: Dropped deprecation-related tasks and tests for xmpp_server role:

- Migration from Prosody project repositories should have been done
already as part of the 7.0.1 release.
- Simplifies the code a bit.
- Drop leftover deprecated library plugin path.

MAR-189: Refactored web_server tests to be less hostname-dependent:

- Use the inventory name (alongisde distribution version) in places
where it's possible and makes sense to do so.
- Rearrange the IP allocation a bit to make more sense.
- Drop architecture information from the hostnames.
- Make the connectivity test operate over a matrix of input
parameters.
- Replace singular use of wget for testing with curl.

MAR-189: Refactored admin acocunt handling in the ldap_server role:

- Get rid of the admin entry from the directory, and resort to using
the directory's olcRootDN/olcRootPW attributes instead. Aligns
Buster package deployment with Bullseye one, as implemented via fix
for the following Debian bug:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=821331

- Add the helper filter plugin to deal with calculating the salted
SHA1 checksum.
- Drop the architecture from Molecule instance names.
- Move the IPs around a tiny bit for Molecule instances.

MAR-189: Remove deprecation-related tasks and tests for database_server role:

- These were relevant in some older versions of Debian and needed
during upgrades from versions that still employed passwords for
system logins/tasks.

MAR-189: Added support for Debian 11 Bullseye to backup_server role:

- Drop the architecture version from the test machine names.

MAR-189: Disable the legacy iptables tools by effectively renaming them:

- Somewhat more forceful but better way to deal with ferm in Bullseye
explicitly using the legacy tools for some unspecified compatibility
reasons.
- Renders the tools unusable because the calling name has
changed (they are all symlinks to the same file).
- Not necessarily required on Debian Buster, but it also won't cause
any damage there either.

MAR-189: Added support for Debian 11 Bullseye to common role:

- Drop the architecture suffix from all machines.
- Introduced a hack/patch for Ferm utility that disables use of legacy
iptables tools.
- Minor fixes around package name differences compared to older
distribution.
- Use versioned binary name for Python 2.7.. Bullseye does not
default/have /usr/bin/python pointing to Python 2.7 binary.

MAR-189: Added support for Debian 11 Bullseye to backup role:

- Drop the 64-bit architecture indiactor from the VMs.

MAR-189: Added support for Debian 11 Bullseye to backup_client role:

- Duplicity on Buster and Bullseye uses different Python version (2 vs
3), install the correct Python pexpect package.
- Switch the helper backup server to using Bullseye, and tweak its
SSHD configuration accordingly.

MAR-189: Refactor hostname pattern for backup_client role (buster/bullseye/bookworm):

- Multiple releases one after the other have names that begin with
letter b, making it necessary to use more than just one letter.
- Use full distro codename, but shorten the parameters to param in
order to avoid issues related to 32-character username limits (when
bak-HOSTNAME user gets created).
- Drop some leftover references to Debian Stretch.
- Drop the arch from hostnames - default is to use 64-bit boxes
anyway.

MAR-187: Reorder the deprecation tasks for xmpp_server role to make the runs reliable:

- Deprecated apt repository really needs to be removed first in case
it has an unresolvable URL (so the backports repository cache update
would trigger correctly).
- Use the file removal for Prosody repository as well to make sure the
file is dropped.

MAR-186: Reorder the deprecation tasks for xmpp_server role to make the runs reliable:

- Deprecated apt repository really needs to be removed first in case
it has an unresolvable URL (so the backports repository cache update
would trigger correctly).
- Use the file removal for Prosody repository as well to make sure the
file is dropped.

MAR-185: Fix the commit command used during the release process:

- The alias commits is no longer used, and OpenPGP signatures are
implemented via git configuration instead.

MAR-183: Use local caching and serving of ClamAV database files:

- Helps avoid getting stuck due to hitting the upstream rate limiting,
and also speeds-up the database downloads.

MAR-183: Drop the create/destroy playbooks for Molecule tests:

- These playbooks are automatically populated by Molecule runs, and
only useful changing in very specific circumstances.
- Solves issues about some missing functionality due to oudated
playbook code (like mounting of share directory on host with
Vagrant).

MAR-184: Update package versions for pip upgrade checks virtual environments:

- Should provide better test coverage compared to previously since
newer versions of pip-tools have slightly different ways of resolving
packages, as well as output formats.

MAR-182: Added ability to specify input requirements for running pip package upgrade checks against helper virtual environments:

- These environments are used for running the package upgrade checks
themselves.

MAR-181: Refactor the Prosody package version checks:

- Move the Prosody package version check into default set of tests.

MAR-181: Deploy Prosody modules (in order to use the LDAP authentcation):

- Replaces the rolled-out-by-hand authentication module, making it
less dependent on upstream repository.

MAR-181: Install Prosody from Debian backports repository:

- This way we should be able to get way more features available, and
reduce chances of breaking upgrades from upstream project towards
Debian-provided packages due to eventual bigger differences between
the nightly builds and official releases.

MAR-181: Use Debian-provided Prosody package instead of project repository:

- Upstream repository has a tendency to drop support for older Debian
releases, and to completely wipe old version repositories.
- It should be way less hassle to simply start using the
Debian-provided packages instead.
- Introduces deprecation tests to check if the role will also clean-up
the non-Debian packages.

MAR-181: Parametrise XMPP client tests:

- Reduces code duplication and makes it easier to expand list of
tested accounts.

MAR-181: Added workaround for Debian Buster tests:

- The upstream has dropped the repositories for Debian Buster.
- Depend on alternative repository set-up on Majic servers.
- Not a permanent fix, but at least it keeps the tests going.

MAR-181: Fix incorrect IP address in tests for xmpp_server role:

- Should match the parameters-optional-buster server.

MAR-181: Use Debian-provided Prosody package for testing optional parameter:

- Still properly tests the role, while at the same time making it
possible to use custom apt repository for Debian Buster (due to
Prosody project dropping all repository archives for it).

MAR-181: Drop support for Debian 9 Stretch from the xmpp_server role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.
- Drop Stretch-specific workarounds, code, and tests.

MAR-181: Rename the private signing key for Prosody repository:

- New names make a bit more sense, and avoids Emacs trying to decrypt
the file.

MAR-181: Drop support for Debian 9 Stretch from php_website role:

- Keep the mail alias step - it is still relevant for Debian Buster.

MAR-181: Drop support for Debian 9 Stretch from web_server role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.
- Drop Stretch-specific code and tests.

MAR-181: Increase memory for mail_server role test machines:

- ClamAV eats-up quite a bit of memory, and 1536MB is not enough. Most
likely the memory usage will grow over time as the anti-virus
database grows since it is loaded up into memory.

MAR-181: Drop support for Debian 9 Stretch from mail_server role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.
- Use Debian Buster for helper machines.
- Drop Stretch-specific code and tests.

MAR-181: Drop support Debian 9 Stretch from mail_forwarder role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.
- Use Debian Buster for helper machines.

MAR-181: Remove release-specific code for database role tests:

- Code was present due to difference between Debian Stretch and Debian
Buster.

MAR-181: Drop support for Debian 9 Stretch from ldap_server role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.
- Drop the workaround for unsupported TLS ciphers on Debian Stretch.

MAR-181: Drop support for Debian 9 Stretch from database role:

- Bump VM memory to 512MB (otherwise MariaDB fails to start up).

MAR-181: Drop support for Debian 9 Stretch from the backup_server role:

- Switch to using IPs from VirtualBox default allowed host-only
network subnets.

MAR-181: Drop support for Debian 9 Stretch from the backup_client role:

- Provide more details on use of pexpect+sftp backed for
Duplicity (backend has to be used on Debian 10 Buster as well, not
just Debian 9 Stretch).
- Switch to using IPs from VirtualBox default allowed host-only
network subnets.

MAR-181: Dropp support for Debian 9 Stretch from the common role:

- Drop platform name from all helper VMs.
- Switch to using IPs from VirtualBox default allowed host-only
network subnets.