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/backend/statistics.go

@@ -59,7 +59,8 @@ type soundtrackRow interface {
 	repository.GetMostPlayedSoundtracksWithSongsRow |
 		repository.GetLeastPlayedSoundtracksWithSongsRow |
 		repository.GetLastPlayedSoundtracksRow |
-		repository.GetOldestPlayedSoundtracksRow
+		repository.GetOldestPlayedSoundtracksRow |
+		repository.GetAllSoundtracksWithSongsRow
 }
 
 func toSoundtracks[R soundtrackRow](rows []R, err error) ([]SoundtrackWithSongs, error) {
@@ -106,6 +107,11 @@ func parseSongs(data []byte) []SongInfoForStats {
 	return songs
 }
 
+// AllSoundtracks returns every soundtrack with its songs, sorted by name
+func (s *StatisticsService) AllSoundtracks(ctx context.Context) ([]SoundtrackWithSongs, error) {
+	return toSoundtracks(s.q.GetAllSoundtracksWithSongs(ctx))
+}
+
 // MostPlayedSoundtracks returns the top N most played soundtracks with their songs
 func (s *StatisticsService) MostPlayedSoundtracks(ctx context.Context, limit int32) ([]SoundtrackWithSongs, error) {
 	return toSoundtracks(s.q.GetMostPlayedSoundtracksWithSongs(ctx, limit))