GPG signed commits

Closes #20268

See merge request !9546

Remove superfluous tags in RSpec examples.

Closes #34319

See merge request !12754

Ensure test files are deleted after fs metrics gathering run

Closes #35457

See merge request !13080

remove extra space

See merge request !13114

Fix the `/projects/:id/repository/branches endpoint` to handle dots in the branch name when the project full patch contains a `/`

See merge request !13115

Support custom directory in gitlab:backup:create task

See merge request !12984

Compile JS lang files before webpack compile

Closes #35615

See merge request !13122

when omitting the end part of the key ('-----END PGP PUBLIC KEY
BLOCK-----') the error message was not about the key anymore, but about
the missing fingerprint and primary_keyid, which was confusing for the
user.
the new validation checks that the end also matches the expected format.

we actually don't need a limit on the column itself for MySQL to work.
we need to set a length on the index.

also:

* reorder table columns
* no need for `add_concurrent_index`
* no need for explicit index removal on `#down`

other than just removing a key, which doesn't affect the verified state
of a commit, revoking a key unverifies all signed commits.