ci: Python version, nodejs and OS

[psaiz]

Increase versions of:

• OS, from 9.3 to the latest 9 (9.7)
• Python, from 3.9 (deprecated) to multiple versions: 3.12 and 3.11

Change the name of the image to contain the python version (almalinux-3.12, for instance)
Declare the nodejs version at the top of the dockerfile

[slint]

@psaiz I was away when this took place, but see also #86 and my attempt at implementing this (but also "thinning down" the image size) in #87. It's a bigger change of course, so personally I'm happy with just merging this small incremental change from this PR.