Solve window <-> process association

[kraleppa]

So there is a problem in LiveDebugger that is painful for us from the beginning - which is finding association between browser window where debugged application is running and LiveView process on the server which is responsible for rendering this application.

This is a problem for us in two cases:

1. Sending messages and receiving messages via debug socket to/from the browser window (e.g. when we want to highlight a specific element) (associated with Create a WebSocket connection between LiveDebugger and debugged browser window #473)
2. Finding successor of given LiveView (associated with Better successor LiveView discovery #410)

Both of this cases are not solved ideally and rely on the socket_id that is not unqiue, which could result in weird bugs.

So in the browser currently we have two things:

• window_id which is our custom identifier of browser window
• socket_id which does not have to be unique in the whole BEAM node (there might be liveview in different window with the same socket_id - especially problematic in case of nested LiveViews)

We'd like to have a following certain associations %{window_id => lv_pid} and %{lv_pid => window_id}. If we had these information we could solve these cases in a proper way

The goal here is to research if we're able to create above association and refactor those cases to use it

[kraleppa]

socket_discover_controller.ex could also be refactored after solving this issue