MAR-218: Switch to using fully-qualified collection names for all tasks:

- Ensures there is no ambiguity when invoking a module.

MAR-218: Quote all octal values in YAML files:

- Fixes linting errors, and ensures there is no ambiguity in case of
YAML specification changes.

MAR-114: Updated task syntax for ldap roles:

- Updated ldap_client and ldap_server roles.
- Added and removed quoting where it makes sense.
- Switched to using expanded syntax (instead of one-liners).

MAR-26: Implemented scaffolding for testing the ldap_server role:

- Fixed role documentation and example for the ldap_server ldap_entries
parameter.
- Fixed missing leading zero when setting mode for deployed files.
- Marked certain tasks for skipping Ansible linting on.
- Fixed invocation of local LDAP commands to use unix socket out of the
box (don't depend on LDAP client configuration).
- Default to state 'present' for ldap_entry (makes things a bit more
readable/clear).
- Added test data for backup and TLS.
- Added dummy default test file.

MAR-23: Implemented tests for the database role:

- Updated test playbook to set-up backup_server as separate play in order to
avoid skipping of backup_client role.
- Updated test playbook to correctly set-up a single backup client.
- Do not manage permissions on /srv/ directory in database role. This can
interfere with backup client access.
- Do not manage permissions on /srv/ directory in ldap_server role. This can
interfere with backup client access.
- Implemented common tests.
- Implemented tests related to database backup.