Add GET /api/v1/statistics/soundtracks with every soundtrack and its songs

The other soundtrack statistics are capped at 100, so a client that shows every soundtrack (the MusicPlayer statistics tab) had no way to get them all. This one has no limit and is sorted by name.

internal/testutil/fakedb/fakedb.go

@@ -391,6 +391,10 @@ func (s *Store) GetOldestPlayedSoundtracks(context.Context, int32) ([]repository
 	return nil, s.Err
 }
 
+func (s *Store) GetAllSoundtracksWithSongs(context.Context) ([]repository.GetAllSoundtracksWithSongsRow, error) {
+	return nil, s.Err
+}
+
 func (s *Store) GetNeverPlayedSoundtracks(context.Context) ([]repository.GetNeverPlayedSoundtracksRow, error) {
 	return nil, s.Err
 }