Add WebSocket functionality to WebRTC testing feature

[rchldn]

Is your feature request related to a problem? Please describe.
The current WebRTC functionality only supports manual copy/pasting of SDP offers and answers. This proves problematic for longer video channel SDPs which can only be exchanged over email.

Describe the solution you'd like
Completing a WebSocket implementation for the WebRTC feature would allow users to exchange SDP information over a server.

Describe alternatives you've considered
The manual copy/pasting works, but is cumbersome and error-prone.