Replace XMPP by Websockets

[sampaccoud]

Feature Request

Is your feature request related to a problem or unsupported use case? Please describe. We want to replace XMPP by websockets

Describe the solution you'd like

• [x] Add a websocket feature using Django Channels
• [ ] Refactor "join the discussion" to use websockets
• [ ] Refactor the chat to use websockets
• [ ] Remove dependency to Prosody, conversejs and XMPP

[lunika]

Also remove all API polling. Today when we want to update an object state (video, documents, TTT, etc) we have to fetch the api and polls it. We also have to determine what is sent throught when an object has changed. Should we send the object payload and an event telling the front that there is an update and the client should fetch the API to retrieve fresh data ?

[lunika]

And this issue must be made in multiple PRs.