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.

This reverts commit 27202e32.

The whole episoide with adding 10.2 and removing it was stupid. This and a lot of other
mess needs to be reverted back. This revert will fix the autopkgtests so they pass.

- extend too short package description
- add DEP-3 headers to patch
- remove unused override

This reverts commit c0a24c72.

Re-enable them later again when there is a DD with full upload
priviledges to sponsor the upload.

It didn't make sense to have them. If users want to pin to certain
version of MariaDB, they will only do so for the client and server
packages.