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

- Updated tests.
- Updated role reference documentation.
- Updated role metadata information.
- Refactored IP plan for the test machines for better separation
between different types of machines and versions.
- Parametrised tests for limited connectivity using the maintenance
mode.
- Don't use MariaDB compat package in tests - name differs between
Debian 9 and Debian 10, and relevant parameter is already getting
tested properly using the remaining packages.