fix(lavalink): drop spotify-tokener, lavasrc uses client credentials

- spotify URL resolution was broken (500 NPE): preferPartnerApi +
  customTokenEndpoint depended on dead spotify-tokener (-32000)
- remove tokener service from compose, remove dead SPOTIFY_* env from
  bot container (bot code never used them)
- spotify metadata now resolves via standard client credentials,
  playback is mirrored to SoundCloud via scsearch providers (ISRC/QUERY)

lavalink/application.yml

@@ -28,8 +28,6 @@ plugins:
       countryCode: "RU"
       playlistLoadLimit: 10
       albumLoadLimit: 10
-      preferPartnerApi: true
-      customTokenEndpoint: "http://spotify-tokener:8086/api/token"
     applemusic:
       countryCode: "RU"
       mediaType: "music"