Sync favorites from ListenBrainz to Jellyfin

[lyarenei]

Revisit favorite sync feature:

• ~JF -> LB: improve experience and allow syncing immediately after favoriting a track in JF~
  • ~Only if (track) MBID is available~
  • ~Optional and can be turned off (default on)~
  • Split off to #82
• LB -> JF: Pull loved tracks and mark them as favorite in JF
  • closes #32
  • Works only with MBIDs
  • Scheduled job, ~configurable period (default 30 days)~
  • ~Selective sync per user~