automate pushing to quay.io registry for apptainer images in clustbench

[btraven00]

We should not rely on manual pushes.

[imallona]

I find friendly to have such feature as part of the CLI, such as ob software build apptainer, ob software push apptainer or similar.

[btraven00]

When I created this issue, I was referring to the example benchmark, so that's a github automation.

We had deleted the "software" code in the past under the agreement that it was not ob responsibility to build packages, images or such, and that it complicates testing. But we can always introduce it again.

I would ask:

• priority - 0.4.0 or post?
• commit to not to test the full integration, just checking that the command line that we execute is roughly correct (it's not our job to test that apptainer API changes, etc).
• track on a new issue