Check browser WebRTC support

[santakadev]

When a user opens P2P Editor in a browser that does not have WebRTC support, we need to tell him/her to upgrade his/her browser.

Message

P2P Editor can't run in your browser 😞
Please, upgrade your browser or try it in another one.

Implementation suggestion

webrtc-swarm has a property for checking if browser supports WebRTC https://github.com/mafintosh/webrtc-swarm#swarmwebrtc_support

Browser support:

• Browsers WebRTC support by caniuse
• Browsers WebRTC support by Wikipedia