Add a basic 404 page
As part of #72 (closed), we should have a separate page for any 404s hit, rather than being just the generic error page.
Edited by username-removed-259647
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
As part of #72 (closed), we should have a separate page for any 404s hit, rather than being just the generic error page.