[kde-telephony-daemon] Pause media players on incoming call
When receiving a call you want to be able to talk without any playing music interfering. Also you want to hear the actual ringtone instead of the music.
Pause all media players when a call is received. Unpause them when you reject a call.
Initial work: !66 (closed)
Implemented with https://github.com/sailfishos/qtmpris/
Contributes to #24 (closed)