Spotify App needs refactoring to reduce code repetition

We can spin these lines off into a separate file to stop repeating ourselves
```
    cache_handler = spotipy.cache_handler.CacheFileHandler(cache_path=session_cache_path(request))
    auth_manager = spotipy.oauth2.SpotifyOAuth(cache_handler=cache_handler)

    spotify = spotipy.Spotify(auth_manager=auth_manager)
```