Sendspin support (synchronized playback from Home Assistant)

Sendspin is an open standard by the Open Home Foundation for a synchronized music experience across multiple devices and rooms.

Integrating sendspin, would enable LibreELEC devices to play synchronized audio, e.g. from MusicAssistant.

There might be two ways to integrate sendspin:

• Implemented in Kodi
• As standalone service in LibreELEC (this feature request)

Implementation: Like snapclient, we could use this existing sensdspin implementation and run it as LibreELEC service.
Running the sendspin-cli daemon will announce this devices via mDNS in the network. Thus, LibreELEC could easily be picked as a synchronized speaker, e.g. by MusicAssistant or Home Assistant.

Sendspin CLI: https://github.com/Sendspin/sends…n-systemd-linux

References:

Note: libportaudio2 is required by sendspin-cli