add method and route to search across tracks, albums and artists.

+ break models into separate files
+ same for the utils and setup

app/db/sqlite/playlists.py

@@ -4,7 +4,8 @@ from collections import OrderedDict
 from app.db.sqlite.tracks import SQLiteTrackMethods
 from app.db.sqlite.utils import SQLiteManager, tuple_to_playlist, tuples_to_playlists
 from app.models import Artist
-from app.utils import background, create_new_date
+from app.utils.generators import create_new_date
+from app.utils.threading import background
 
 
 class SQLitePlaylistMethods: