Peer: Allow "muting" (de-syncronized) Friend

[hnryjms]

Per a discord discussion, we thought it might be nice for one person to attend the party and de-syncronize from the group. This might be if they joined a movie late, and the main group decides to have a popcorn break, and you stay to catch up in the video while they're gone, and then join as your browser crosses their location.

I see a few things being necessary:

• Predication system that can calculate where a Friend[] is, based on their last status report

  • (video.paused ? 0 : (Date.now() - lastStatus.date.getTime())) + video.currentOffset
    

• Automatically rejoin if your playtime synchronizes with the play time of people who are synchronized
• Prevent the last person from "muting" themselves, as then there is no true play time.
• Add a Split Viewing/Synchronize button to the Info page of the UI (code should exist as commented out)
• Handle muting in the Host class