Handle Spotify Rate Limit

[MrKrisKrisu]

As more and more Users register at KStats the algorithmus to check every user every minute is a little bit too much for the Spotify API. There should be a way to minimize these requests.

[2020-08-19 13:23:07] staging.DEBUG: [Spotify] [CatchNowPlaying] Checking User xxx / xxx
[2020-08-19 13:23:07] staging.ERROR: Error while trying to retrieve currently-playing from Spotify API. StatusCode: 429  
[2020-08-19 13:23:07] staging.ERROR: {
  "error": {
    "status": 429,
    "message": "API rate limit exceeded"
  }
}  

[MrKrisKrisu]

Reverted in eb25872
With this solution not all users got catched well.
Anyone some Ideas? :/