Improve Web Page Loading Lifecycle

[davertay-j]

When a user enters something into the search bar, there are three "stages" before anything useful can be presented in the UI:

1. figure out what URL to load
2. get the WKWebViewConfiguration loaded and inject scripts/handlers
3. kick off the WKWebView load and await the DOM structure

These things are kind of dis-joint right now and the fracturing is manifesting as complexity and hairs in the view models and glue logic.

It grows more hairs once the page is loaded and the user and/or Js starts interacting and firing delegate callbacks.

This ticket is to figure out a way to cleanly model this system such that it integrates nicely with the UI navigation as a whole. Right now it is kind of prickly and the biggest drawbacks are it does not support multiple active tabs or deal with web navigation sensibly, especially how that limits the ability to do granular Bluetooth permissions.