Allow Interrupt/pause/resume/mute/unmute by play_id

[Object905]

For some scenario I want to play background noise/music, while continuing call flow with play/tts commands.
Both background play and such commands have track_id=server-side-track, so concurrent play/tts can't be controlled separately.
Pause/Resume commands don't even allow to specify track_id.

[Object905]

Also Pause/Resume don't seem to work as expected. On pause I get TrackEnd event and Resume doesn't work after this.

Also sending Mute/Unmute command without specifying track_id='server-side-track' just hangs for me. When track_id specified - its behaving similar to Pause - TrackEnd is emitted and Unmute doesn't work.