[music] Review/update module

[raucao]

Please review the current code, update if necessary, remove log statements (or use the remoteStorage debug logger instead). Also, please format the code properly: 2 spaces indentation, add blank lines where needed, remove trailing whitespace, etc.

[michielbdejong]

This module is used only by https://music-michiel.5apps.com/ which is not currently maintained anymore. When updating the music module, it would be interesting to see how feasible it is to store a significant music collection in IndexedDB.