site autodeployment script

Terrible workaround for Forgejo Actions being a terrible CI.

Watches for main branch on site repo, builds with Podman, tags as golden, pokes systemd.

Feel free to re-engineer into something less bad.

debugging

On szalotka:

$ journalctl -xfeu site-autodeploy

Feel free to just poke sudo podman and images, retag whatever as golden, then restart podman-site.