MAR-242: Added role parameter to xmpp_server role for configuring uploaded file expiration (XEP-0363):

- Also reworded and harmonised related role parameter descriptions.

MAR-242: Added role parameters for xmpp_server role to configure HTTP file upload limits (XEP-0363):

- Refactor the daily quota tests to be a bit more flexible.

MAR-243: Drop inventory_hostname use from tests where possible:

- Primarily focused on Ansible playbooks and variable files.
- The variable is still used within some Python test fixtures. Test
behaviour should still be correct, with one advantage being that
lookups should be much faster than using the setup module (which
would require running Ansible code on each remote/test machine).

MAR-230: Updated documentation, inline comments, and some tests related to TLS configuration:

- Documentation and comments should be a bit more consistent across
the roles now.
- Try to follow same rule for inclusion of singular TLSv1.2 cipher
across the board in affected tests.

MAR-230: Drop support for older TLS versions from the xmpp_server role:

- Update documentation.
- Include TLSv1.3 ciphers in default configuration for documentation
purposes - although ciphers are not configurable.
- Update the tests. Drop the workarounds for enabling the older
versions via OpenSSL policies.

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-174: Enable Message Carbons (XEP-0280) and Message Archive Management (XEP-0313) via xmpp_server role:

- Updated release notes.
- Updated role reference documentation.
- Enable the two modules via Prosody configuration file, and set the
archive expiration configuration option for Prosody.
- Updated tests.

MAR-164: Harden the c2s TLS configuration for the XMPP server role:

- Updated the xmpp_server role.
- Added (optional) xmpp_server_tls_protocol and
xmpp_server_tls_ciphers parameters for specifying the desired
TLS protocol version and ciphers for the c2s connections.
- Updated XMPP server configuration to introduce separate TLS
configuration for the s2s and c2s (legacy included) connections.
- Drop support for Prosody 0.9 since it is not possible to have
separate TLS configuration for c2s and s2s connections.
- Updated role reference documentation.

MAR-150: Use fixtures for X.509 artefacts in the xmpp_server role:

- Removed the statically generated artefacts.
- Generate X.509 artefacts for tests using Gimmecert.
- Updated paths to point to generated artefacts.
- Introduced cleanup playbook for removing generated artefacts.

MAR-162: Make the xmpp_tls_certificate and xmpp_tls_key parameters mandatory in xmpp_server role:

- Dropped the defaults from wsgi_server role.
- Updated group variables in role tests.
- Changed the key/certificate file extensions to be more descriptive.
- Updated role reference documentation.
- Updated usage instructions to include the mandatory parameters.
- Deduplicated tests for the TLS files.

MAR-138: Switch to using Prosody stable branch nightlies:

- Introduced additional parameter for specifying name of Prosody
package to install.
- Updated tests.

MAR-132: Added support to xmpp_server role for Debian 9 (Stretch):

- Updated tests to include Debian 9 in testing. Existing private keys
are reused where possible (since most of the naming is identical
between the machines with jessie/stretch).
- Updated invocation of sendxmpp in tests as workaround for
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=854210.
- Updated testing of imported keys to accomodate differences between
gpg/gpg2 (used by apt-key in Jessie/Stretch).

MAR-129: Updated xmpp_server role for Ansible 2.5.x and new Molecule:

- Include top-level lint configuration in test configuration.
- Fixed linting errors.
- Moved test playbook variables into group_vars and host_vars.
- Fixed deprecation warnings from Ansible.
- Updated how hosts are referenced within tests.