This aligns the Ladybird console implementation with the Browser console
a bit more, which uses OutOfProcessWebView for rendering console output.
This allows us to style the console output to try and match the system
theme.
Using a WebContentView is simpler than trying to style the old QTextEdit
widget, as the console output is HTML with built-in "-libweb-palette-*"
colors. These will override any color we set on the QTextEdit widget.
While this adds a fair bit of widget code, we're also increasing code
sharing by using the same bits in WebContentClient for interacting with
the JS console.
That said, we should look for more ways to share code here.