Create an official docker image

[SckyzO]

Hi all,

I use docker on my dev stack, and I think it will be very interesting to have an official docker image of slurm exporter.

Regards,

[mtds]

@SckyzO We did not have the chance to test a Docker image in our production cluster: we mostly use Apptainer/Singularity and recently started dabbling with Podman, so I can only propose you to test the dockerfile submitted via PR #85.