Proper hot reloading using react fresh/react-refresh

[wokalski]

Currently there's a simplistic hot-reloading implementation. On an edit to a file on the server:

1. server is killed
2. The connection between client and server is killed
3. client polls until server is available again
4. client makes a request for the currently shown component
5. server renders the component from scratch

It's good enough but it's a little bit slow. If we incorporate react-refresh it should work quite better - it wouldn't require rerunning the server which takes a considerable amount of time. This is obviously to be investigated but it should be a big productivity gain.