Switch from Web Sockets to Long polling

[virgile-dev]

Bug Report

Problematic behavior
Websockets are not compatible with internal networks and security configuration.

Expected behavior/code
Replace websocket with Long Polling.
Which means we need to make changes to hoccus poccus and Y.js

[YousefED]

Thanks for adding this. Did we confirm this is really the issue for certain users?

Kevin's first thoughts on this are here: ueberdosis/hocuspocus#95 (comment) and this specifically might be concerning:

A quick web search revealed that the very same Antivirus software that can do this if (mis)configured, also blocks long-pulling

I'm quite sure we can add support for it but it will be quite a bit of work - so it would be great if we can test whether it actually fixes the issue for those setups