Widen Moodle per Pawjwp

Changes a number of Moodle design elements to make it use space more efficiently, including widening it so it doesn't limit itself to less than half the screen. This is designed and tested only for the new default Moodle theme (Boost).

Currently works on websites with the "moodle.*.*" url format (all sites with the "moodle" subdomain)

Requires access to all sites only because subdomain match strings in the manifest.json aren't supported by default, so the matching has to be done with js.