Move jobrunner to using a docker image with autodeployment.

[bloodearnest]

This is patterned on how we run airlock:

• uses docker compose to run and manage restarts and logs
• a systemd timer/service to regularly pull down new images

We get to remove the code/lib dirs, and some of the awkward scripting.

Jobrunner has a lot of management commands, but those are mostly abstracted behind just, and I have added any that were missing to the justfile.

Deploying this will require some post install manuall cleanup of code/lib dirs.

It was difficult to break up into small commits, at its a big refactor that touches a lot of related things.