Implement action types pause, resume and restart

[Orbiter]

Describe the solution you'd like
If a media file is played, it is possible to say "stop" to stop playing. Similarly, with the following action types, it should be possible to

• pause the playing of a media file (youtube, mp3 etc) with the action type pause
• resume the playing of a media file which has been paused with the action type resume
• restart the playing of a media file (either currently playing or paused) with the action type restart

Additional context
Examples:
https://api.susi.ai/susi/chat.json?q=pause

"actions": [{"type": "pause"}]

https://api.susi.ai/susi/chat.json?q=resume

"actions": [{"type": "resume"}]

https://api.susi.ai/susi/chat.json?q=restart

"actions": [{"type": "restart"}]

[Orbiter]

related: fossasia/susi_iOS#395 fossasia/susi_android#1607 the issues for Android and iOS

[sansyrox]

I would like to work on it

[sansyrox]

@Orbiter , right now we pause the Music to process the second query. Now we would have to follow a different approach. Should we be reducing the volume of the music player instead??

[hongquan]

have to follow a different approach

@stealthanthrax Can I learn more about the context? Which approach is that? Where is it described?

[tmccormi]

Adding an action to change the volume up and down seems to be relevant for this feature request as well