Add SharePlay Support

[thrasos-dev]

Is your feature request related to a problem? Please describe.
There’s no easy way to watch videos in sync with friends through KSPlayer. We have to manually coordinate playback, which never stays aligned.

Describe the solution you'd like
Add SharePlay support so users can watch videos together over FaceTime with synced playback and shared controls.

Describe alternatives you've considered
Tried screen sharing and manual syncing.

[DrHurt]

That requires AVPlayer which I've been asking Kingsley to implement more broadly as it will also support atmos.