[ci] self contained test container

[abhinavDhulipala]

Get slurmd and slurmctld working in a "single node" slurm docker install

[abhinavDhulipala]

Now we can simply build our image run our c extension within the container.

# takes 5 to 10 min
just docker
# use vscode to open a dev container with the following running container
docker run --name slurmcprom-dev -d slurmcprom sleep infinity
# then attach to this container w/ vscode

[abhinavDhulipala]

Now we can begin launching jobs and e2e testing all from a single container :)