Investigate source management endpoints

[gmuth]

POST /removeMusicServiceAccount to the soundtouch device

triggers

DELETE /marge/streaming/account/{account}/source/{sourceid}

I'd assume there are more generic endpoints to manage sources and music service accounts (anonymous or individual)

Reference:
https://github.com/thlucas1/homeassistantcomponent_soundtouchplus/wiki/SoundTouch-WebServices-API#music-service---remove-station