Azure webpubsub

[byrond]

This likely won't be the final implementation but represents most of the changes that need to be made to make y-webrtc compatible with Azure Web PubSub as a signaling server. The final solution will be to make y-webrtc extensible for swapping out signaling server code. Currently, y-webrtc makes assumptions about the message format and structure, which makes it difficult to plug in a different signaling server.

[byrond]

I copied this code from a local copy of the module that was renamed to y-webrtc-azure-webpubsub

[byrond]

This doesn't actually need to extend Observable since the client subscribes to events, not this class.

[byrond]

I think we can create some SignalingConn methods to abstract the subscribe and publish calls in the global functions. One thing I'm not sure about is when we extend SignalingConn, we don't actually want to use any of it but would be required to call super() in our derived class. We could create a base class, but the existing SignalingConn needs to extend ws in lib0/websocket.

[byrond]

Closing this, which was opened on the wrong repo. We will eventually separate this work out into a PR for y-webrtc that makes the signaling connection extensible/swappable and a separate library that adds support for using Azure Web PubSub as a signaling server.

Sorry for the confusion. GitHub insists on making the original repo the base for PRs instead of the fork.