Display notification on socket disconnect/failure

[alex-saunders]

Currently, if the socket connection between the client & server dies, everything starts to silently fail and the user is given no indication of what is going on (apart from an error in the console). It would be good to alert the user via notification that the connection has failed (and maybe when they click the notification, it would attempt to reconnect to the server?).

I think using the browser's native notifications (like with the outdated dependencies notification) would suffice, there shouldn't be a need to create our own notification component/UI.