Add WebRTC wrapper and backend

Adds the following features:

Connect with Name Server to register a Master and setup WebRTC connections.
Start/Stop a Master to make it available/unavailable for WebRTC connections.
Connect/Disconnect multiple Clients to a Master using the Master name.
Authenticate a client.
Transfer data between Master and Clients.
Synchronize operations between the Master and Clients via WebRTC backend.
Connect to a private STUN-TURN server (By default connects to public STUN servers).
Detailed documentation.

The Name Server (https://github.com/anto-christo/WebRTCNameServer) has been implemented using FrappeJS.