mediawiki-pages: rename to Community Requests, add peer gadget

WARNING: run npm run nuke before checking out this MR. Then after checking out this MR, run npm run setup and follow instructions. You'll want to test with the gadget enabled.

This changes the page titles to match our decided internal name - Communtiy Requests. Now everything should live on or as a subpage of Community Requests. Redirects are still left for convenience, TBD if those will ship to prod.

Make all gadget-powered pages (either now or in the future) be in [[Category:Community_Requests/Intake]], and have the gadget load only on those pages.

Add peer gadgets to hack in the page titles before the gadget loads.

Forewaring that these pages may change one more time when we decide on our user-facing name.

Bug: T362809