Add config database table and enable crud page.
Also add cache controller, model and view and routes for these pages.
Make the JavaScript display a message when changing the state of
development mode.
It's now possible to disable the Cloudflare cache during development,
so the hacky workaround with the random number in the CSS/JS URLs is no
longer needed.
Development mode is automatically disabled by Cloudflare after 4 hours.
Riyyi