Temporarily get Salsa-CI pass and not stall work with broken pipeline
and instead be green for now and raise alerts only if new Lintian errors
are introduced.

- Clean unused overrides.
- Clean away copyright paragraphs about files that no longer exists.

- 10.1 includes Galera by default. Include a Galera config section,
  a bootstrap init section and wsrep etc files in the server.
- Extend build and install dependencies to accommodate for Galera etc.
- Compare *.cnf files, update option names.
- Compare *.install files, update files lists.

Systemd changes are excluded for now.