Fixes to configuration

metasrht now runs and is accessible. The /register path is broken
though, and I'll need to play with NGINX proxying to fix it.
The container-internal web port (8080) is being appended to the URL. The
simplest solution is probably to switch the web port back to 80.
Need to setup SSL/TLS certificate as well, so that I only have to
migrate this once.

A minor issue: the web page reads "Welcome to localhost:5000!". It seems
the `origin` key in the config files needs to be the public address, not
the internal address.

Also, now ready for persistent git repos.

Refactoring

The site is no more functional now. But the databases are now in
separate containers, and there is a working recipe for managing the
database initialization/migration (via `make dbinit` and `make dbmigrate`).
This should speed up image builds and container starts, and make the
entire development cycle faster.

Sourcehut files have been moved to `sr/`.