#328 use websocket for bell notifications
I made the websocket update bell notifications. The websocket server is still being called "chat" everywhere, I did not change that because it would involve changing names in our docker images, although I'd prefer a more generic name, as it could be used for even more things in the future.
I'm still working on Push Notifications, I think I'm done with the backend, but the Frontend stuff with the service worker still causes some pain. I created a new issue for that and I'm going to do a second merge request: #336