Draft: Integrating mediasoup + Support the signal communications (backed by Turms server)

[JamesChenX]

https://mp.weixin.qq.com/s/PhKOzA60eXI7LJpqgA5O_w SRS is developing the functions for WebRTC, we may wait for it.

[JamesChenX]

Principle:

• Only WebRTC will be supported, and RTMP will not be supported.
• The workflow of the architecture with the custom signaling servers (Node.js + backed by mediasoup) should be similar to the workflow designed for MinIO servers.

1. For clients, they need to communicate with both turms server and the signaling servers (they're also media servers).
2. For turms servers, they focus on authentication (reuse the logic) and provide plugins (for developers to extend if they want) to direct the signaling servers. e.g. turms servers can give a token to the signal servers (via HTTP/2? or WebSocket?) to tell them if a user takes the token to join a room (via WebSocket), they should approve and let him/her join the room.

Note that ICE has been integrated in mediasoup, so we don't need dedicated ICE servers