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If handleMediaMeta is blocking, the timeout will try to acquire the sync
mutex, but won't manage to do so.
However, this only allows the parser to continue, but my guess would be
that there will still be a thread blocked somewhere

This has better performances than fetching all tracks and check for the
size of the vector

This was causing the insertion assert to trigger, due a thread querying
the database while:
- Holding the cache lock
- Acquiring the database lock
- Inserting the fetched entity in cache if it didn't exist

While another thread was inserting an entity while:
- Holding the database lock
- Releasing it after the insertion was done
- Holding the cache lock
- Checking that the entity didn't exist in cache

Since the locking order wasn't consistent, the 1st thread was
interupting the 2nd before it was done with the entire insertion
method, causing an inconsistent state.

Instead of the function name, display the fully decorated methods &
line, when available

Media now always have a single artist
Artist are being added media
The album artist meta is used to generate the list of artists
The artist meta isn't used for artists list

And fallback to AlbumArtist if no artist is provided

And make it an enum class