Run test suite with a GitHub Workflow

[consideRatio]

I figure this spawner require a systemd environment setup in various linux distributions, but we can get that done I think. We are using this spawner in the TLJH distribution where a basic systemd image built and tljh is installed within the image with systemd.

See the Dockerfile that installs systemd here:
https://github.com/jupyterhub/the-littlest-jupyterhub/blob/main/integration-tests/Dockerfile

[behrmann]

As a word of warning: docker had some animosity towards systemd in the past and went out of its way to make it hard to run systemd inside a container and is probably the last container runtime to not support systemd's container interface. You will probably have more luck running your tests with podman, which in most cases should be drop-in compatible.

That being said, GA run in Ubuntu VMs and just have systemd installed. systemd-spawner doesn't use any too recent featuees, so any recent Ubuntu LTS should be fine.