MAR-226: Harmonise the HTTP header override parameter between the PHP and WSGI website roles:

- Use the new naming/syntax introduced in the php_website role since
it implies less dependence on the backend application (more generic
name for it), and is a little bit saner in terms of not having to
provide quotes as part of the value.

MAR-151: Added support for Debian 10 Buster to wsgi_website role:

- Updated role reference documentaiton.
- Updated role meta information.
- Updated tests.
- Replace the installation of libmariadbclient-dev-compat library with
atftp - the actual package is differently named under Debian Stretch
and Debian Buster (which would complicate the test without any
benefits).
- Drop the fix for root mail alias in Vagrant image - seems it's no
longer a problem.
- Split-up the test for web application user since it's not possible
to keep it all under one parametrised test due to differences in
assigned system UID numbers for Debian Stretch and Debian Buster.
- Make the test for web application user less dependant on what the
actual UID number is in case of default value. By default user
should be created as system user, which means its UID number should
be less than 1000.

MAR-170: Always enforce use of HTTPS in the wsgi_server role:

- Dropped the enforce_https parameter.
- Updated tests.
- Updated release notes.

MAR-148: Fixed the tests for wsgi_website role:

- Fix issues related to newlines in outputs.
- Refactor Python version check to make it more robust.

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

- Set the shell for application system account explicitly (workaround
for Debian bug 865762 in Stretch).
- Updated Molecule tests to cover Debian 9.
- Updated Molecule test preparation playbook to account for a number
of differences between Jessie and Stretch (mainly related to mailing
functionality).
- Renamed a couple of variables in test for sending out mails to make
it clearer what is being looked up as part of regex matching.
- Updated Molecule tests where certain paths depend on what Debian
release they are ran against.
- Split-up Jessie-specific tests into separate file.
- Remove the /bin/ss utility instead of renaming it (testinfra socket
tests do not work with /bin/ss).

MAR-131: Added support for specifying Python version in wsgi_website role:

- Introduced additional role parameter for specifying the Python
version.
- Updated tests to verify new functionality.
- Fixed existing tests to account for differences between Python 2 and
Python 3 - including changes to WSGI test applications.
- Updated documentation, documenting new parameter and fixing one
minor typo.
- Updated release notes.
- Bumped default version of Gunicorn/futures used.

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

- Include top-level linting configuration in test configuration file.
- Fixed linting errors.
- Updated Ansible deprecation warnings related to use of
state=installed with apt module.
- Updated how hosts are being referenced in tests.
- Rename the 'ss' utility in order to properly test socket
connectivity as a workaround for Testinfra bug.

MAR-129: Updated Molecule to version 2.12.0:

- Updated Molecule to version 2.12.0, alongside its requirements.
- Fixed tests for preseed role to account for new paths on destination
servers (change in Molecule).
- Updated wsgi_website test for pacakges installed in Python virtual
environment.

MAR-129: Minor preparation for updating Ansible version:

- Ignore the pytest_cache directory in Git.
- Updated Ansible to latest 2.3.x version in requirements file.
- Make sure the SSH client private keys have correct permissions when
testing the backup_server role (must be 0600), otherwise we get
errors from SSH due to insecure permissions during testing.
- Updated test for testing installed packages in the wsgi_website
Python virtual environment to test against up-to-date
packages. Might be nice to fix this one with something less hacky in
the long run.

MAR-128: Upgraded tests for ROLE_NAME role:

- Switch to new Molecule configuration.
- Updated set-up playbook to use become: yes.
- Moved some preparatory steps outside of the main playbook (eases
idempotence tests).
- Updated tests to reference the yml inventory file.
- Updated tests to use new fixture (host instead of individual ones).
- Switched to extracting hostname instead of hard-coding it in a
couple of tests.
- Fixed some linting issues.
- Updated one of the tests that depend on output of pip freeze due to
new versions of packages coming out.
- Updated hostname to include Debian version (for future expansion).
- Renamded some test data to match new hostname.