major refactoring 😫

- move instances to separate module
- import functions as modules
- add docstrings to helper functions
- add threaded populate() function
- remove unused functions and files
- add typing info to helper functions
- move large functions to separate module
- Introduce independent search input to directory view (demo)
- Handle Ctrl + F (yaay 💪😜)
- few *more* forgotten changes to the client
- phew!

server/app/instances.py

@@ -2,4 +2,6 @@ from app.models import AllSongs
 from app.models import Artists
 
 songs_instance = AllSongs()
-artist_instance = Artists()
+artist_instance = Artists()
+
+""