Video and audio in separate webrtcbins

[danisla]

Fixes #7

• Reduces latency when streaming with audio enabled.
• AV sync is within reason.
• Client connects separate RTCPeerConnections for audio and video.
• Connections use the same config and STUN/TURN servers.
• Backend signal clients and pipelines are also duplicated.
• Removed option to disable audio from client and cli args.

Testing

You can test it with the example docker container like this:

Ubuntu 22.04

docker run --pull=always --name selkies -it --rm -p 8080:8080 -p 3478:3478 ghcr.io/selkies-project/selkies-gstreamer/gst-py-example:testing-ubuntu22.04

For Ubuntu 20.04:

docker run --pull=always --name selkies -it --rm -p 8080:8080 -p 3478:3478 ghcr.io/selkies-project/selkies-gstreamer/gst-py-example:testing-ubuntu20.04

[ehfd]

I am no longer making approvements in the meantime because I don't think I can test these in my limited time.

Let's just merge quickly and sort out the issues later.