Currently, on Serenity, we connect to WebDriver from the browser-side of
the WebContent connection for both Browser and headless-browser.
On Lagom, we connect from within the WebContent process itself, signaled
by a command line flag.
This patch changes Lagom browsers to connect to WebDriver the same way
that Serenity browsers do. This will ensure we can do other initializers
in the same order across all platforms and browsers.
This starts moving code equally shared between the OOPWV and Ladybird
WebContentView implementations to WebView::ViewImplementation, beginning
with the client state.
