Lowercase code name

The code name may be uppercase,
it needs to be converted to lowercase when calling gst.CreatePipeline.

Revert sfu-ws changes

RID/MID has been disabled in pion/webrtc@v3 so we no longer have an
issues signaling.

Force VP8/Opus in sfu-ws

Chrome is generate answers that then fail with SetLocalDescription.
Haven't been able to find the issue yet

Fix typo

negotation -> negotiation

Add twitch example

Show how to consume webcam/microphone and send to Twitch