Stabilize features `patch` and `archive-site`.
The PATCH method has been tested by myself and on Codeberg and found
to work satisfactorily.
Because using PATCH causes the git-pages server to store state that
is not necessarily easily reproducible from any single specific source
(i.e. it stores a composition of many disparate requests), it may be
necessary to back it up. For this, the feature `archive-site` is also
stabilized. It has not seen much use but not providing a backup method
would be a disservice.