Musicbrainz Demo

[Kerollmops]

This PR must not be merged on main. It is only opened to expose the progress made so far on the MusicBrainz demo.

TODO

• [ ] Rebase on main to benefit from security fixes
• [ ] Move the changes to another repository
• [x] Remove the index selector and use the index names directly
• [x] Add an artists index to search in scored artists names
• [ ] Show the artists and genre within the list of musics (in a small list in place of one music)
• [x] Hide the left selector bar
• [ ] Clicking on an artist or genre (or year range) refines the results