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-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-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-173: Switch to using Prosody 0.11 as default version in the xmpp_server role:

- Updated default value for the Prosody package parameters.
- Configure the backports repository on the server, and pin the
lua-ldap package to be installed from the backports
repository (needed for Lua 5.2 support).
- Drop the explicit installation of lua-sec library - it is already
installed as pre-requisite for the Prosody package.

MAR-171: Make the xmpp_domains parameter mandatory:

- Updated release notes.
- Updated role reference documentation.
- Dropped the default value for parameter from the xmpp_server role.
- 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-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-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.

MAR-31: Added scaffolding for testing xmpp_server role:

- Fixed wrong default for xmpp_domains parameter (should be a list).
- Added Molecule configuration file with LDAP server, client, and two XMPP
server instances.
- Added test playbook that sets-up all servers.
- Fixed mode syntax issues (use lead zero).
- Added data required for testing.
- Added dummy file with tests.