MAR-132: Fix virtual environment set-up in wsgi_website role:

- Install more up-to-date version of pip. This fixes some issues
related to pip freeze detecting argparse and wsgiref in virtualenv
as separate packages.
- Remove the pkg-resources package from virtualenv. Workaround for
Debian-specific behaviour. More details at:
- https://github.com/pypa/pip/issues/4022
- https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1635463
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871790
- Deploy Gunicorn requirements file without switching to website admin
user (otherwise Ansible fails to template the file due to
permissions restrictions).
- Updated test for checking packages installed in the virtualenv.

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-118: Replaced handler with parametrised name in wsgi_website:

- Updated wsgi_website role.
- Replaced handler with parametrised name used for restarting a single service
with a generic handler that will restart zero or more services.
- Updated test site roles to introduce explicit handler in them.
- Updated usage instructions to include set-up of explicit handler for
restarting the Wiki service.

MAR-114: Updated task syntax for web server/application roles:

- Updated web_server, php_website, and wsgi_website roles.
- Added and removed quoting where it makes sense.
- Switched to using expanded syntax (instead of one-liners).
- Updated ordering of arguments in task definitions.

MAR-33: Implemented tests for the wsgi_website role:

- Updated test playbook to have better coverage of functionality.
- Fixed some additional permission mode issues (leading zero).
- Use expanded syntax for deploying TLS material in order to avoid mangling of
TABs.
- Implemented proper WSGI applications in order to test everything.
- Implemented tests covering mandatory parameters, optional parameters, and the
use of WSGI requirements/Paster.

MAR-33: Added initial scaffolding for wsgi_website tests:

- Added Molecule configuration file.
- Implemented test playbook that sets-up three separate instances of WSGI
website in order to test all variations of parameters.
- Added name for the set_fact task.
- Fixed linting errors related to mode that lacks leading zero.
- Added skip_ansible_lint tag for command that creates the Python virtual
environment.
- Added missing become keyword wherever become_user is specified.
- Fixed invalid parameter name for specifying if HTTPS should be enforced or
not.
- Added small initial sample WSGI apps that get deployed.
- Added static/media sample files.
- Added TLS material.
- Added initial dummy test file.