From the users' perspective, a media can be considered as removed from
the database as long as it's not part of any listing.
This simplifies the implementation for the clients, and matches the
initial intent of not providing explicit callbacks for external media.

Fix videolan/vlc#26854

Fix #435

refs #435

refs #435

We'll soon have a 2nd similar queue so we need to clarify what kind of
convertion that is

It's never used.

In order to update the duration when a media gets removed, similar to
what was done for the number of tracks for #432

This allows use to react to convertion to/from external media
Fix #432

Instead of manually updating when assigning a track to the genre.
This allows us to update the number of tracks automatically when a media
gets converted to external, mainly following a removal of the associated
entrypoint.
Refs #432

Fix #431

This only ever caught false positive

This reverts commit 433593c5.
This wasn't enough to fix the problem, as a refresh would:
- Invoke flush, setting the flushed flag to true
- Invoke restore, immediatly setting the flag back to false

This saves a bit of duplicated code in each template instantiation

This saves about 20KB in the resulting binary
refs #430

Now that we don't have to manually time the request, we can just return
the result directly

This prevents this common code to be generated for each variant, saving
around 10KB in the resulting binary
refs #430

This doesn't cause a size loss, but it will prevent the same code from
being built again and again from most files

This saves a bit of space in the resulting binary (about 30KB)

This doesn't save space but it prevents the code from being actually
built from pretty much each other source file

This saves about 174KB in a release shared library

Which fixes a constraint violation when removing a media that was
bookmarked.
Fix #429

The temporary table wasn't removed, which isn't an issue as it will go
away when the database gets closed, but it breaks the migration tests

Sprinkling per-version modification isn't readable when there's more
than a couple changes
refs #429

Fix #425

Refs #425

This tests with more than a single track since the genre was deleted
when the number of track reached 0