See #170: exclude by default all channels-related entities from /artists, /albums and /tracks endpoints results, for backward compatibility

See #261: Added a rate-limiting (throttling system) to limit the number of requests handled per user/IP

This reverts commit 8b47af8b, reversing
changes made to c0055b3b.

Fixed #15: Ensure we check for authorization for serving audio files, meaning we don't leak the absolute URL anymore