Expose events related to activity feed buttons #13

Activity feed allows to pause/resume, skip, mute and replay alerts by pressing dedicated buttons which seem to work great when using provided widgets.

But custom ones don't seem to get access to those features. Correct me if I'm wrong but I tried to take a look at the code and WebSocket events only seem to broadcast some internal Angular events.

I think it would be a great addition to expose events related to activity feed buttons (plus initial state, maybe as a new property attached to the onWidgetLoad event data?) so that custom widgets can react accordingly.

Thanks :)