Replace XRMP party system with WebRTC

[chrislatorres]

All of the XRMP party system can be done over rtc now, the data transfer can be the same.

The goal would be:

• drop down in Studio ( https://github.com/exokitxr/studio ) to join a party
• use same syncing model as realitytabs.html
• all of this without any servers to maintain.

The way to share parties is by sharing a link, there could also be a registry, but the registry will not be doing all the serving this time.

In researching for this, came across https://github.com/takahirox/ThreeNetwork , which examples work well in Exokit out of the box:

[chrislatorres]

The best way to go about this is using raw WebRTC and using studio's index.html as the starting point. (can also then connect to the studio UI for a menu)