Async-spotify

Adds:
+ Add multiple tracks to queue

Fixes:
+ Required scopes for auth flow

+ Fixed 25

Breaking Changes
+ Import paths have changed
+ SpotifyPreferences renamed to the correspond auth flow moved to async_spotify.authentification.authorization_flows.*

+ Fixed 20
+ Fixed 22

+ Renamed Preferences to SpotifyApiPreferences to avoid same names
+ Added client credentials workflow

+ Added token expired hook