Support OpenSubsonic API extensions
Add support for OpenSubsonic API extensions. OpenSubsonic is a collaborative effort to extend the Subsonic API in a backward compatible way with additional but optional data. See https://opensubsonic.netlify.app/
It should be investigated for each supported endpoint which additional data fields are defined by OpenSubsonic and for which FW already has data available.
I think this ticket could be tackled step by step by adding data that is available in FW already but right now not exposed via Subsonic.