Consider providing a way to prevent running workshops being automatically restarted after reboot #1136

Currently, a running workshop is automatically restarted after the host reboots. I don't typically want this, and would prefer shutting down my machine to stop any running workshops, though I can see the use case for restarting all running workshops.

It's possible to go under the hood to disable this behaviour with lxc config set --project workshop.$(id -u) <container> boot.autostart=false each time you start a workshop (it seems to only be reset to true on workshop start/launch), but this is not ideal (in particular finding the container identifier), especially for someone who forgets they have workshops running in the first place 😆

It might be nice to be able to pass --no-autostart or similar to commands that launch a workshop, or to be able to define a workshop such that it doesn't restart, or to be able to run a friendlier command to disable autostart for a specific workshop at any time.