sshd configuration

Need to enable TCP forwarding, in order to tunnel SMTP over SSH. This is
preferable to opening port 25 and exposing the mail server.

Version 1.0

Fully functional and mature implementation for x86 and aarch64, for
docker and podman. The process from source code to live deployment is
now reproducible and documented in both the README and the Makefile
recipes.

Git repos are now accessible by SSH or HTTP(S).

The `lists.sr.ht` functionality is deferred as out-of-scope and the
`builds.sr.ht` functionality is permanently declared out-of-scope.
Running the maintenance cron jobs is a TODO, as the relevence to this
project is dubious.