Setup the Alma9 release pipeline

Problem

We currently have a simple mechanism in our CI to do CentOS7 releases of CTA, but it does not work with Alma9.
For now, it has to be done manually in a separate branch:

• #596 (comment 7575228)

Objective

• Setup a new CI pipeline for Alma9 releases.
• It should work in a similar way to the CentOS7 mechanism.
• We should be able to easily select between Alma9 and CentOS7 (or both).