Rebuild released tags

[ntarocco]

We should probably split the GH Actions to do the following:

• [x] Release on tag. For Almalinux only, it should:

  1. build the image
  2. push with tags latest, major, major.minor, major.minor.patch.

• [x] Rebuild on schedule, both for Almalinux and the 2 CentOS 7:

  1. checkout the repo on the latest push tag
  2. build docker images
  3. push same tags to replace the built images upstream (for CentOS, tags are hardcoded with 3.6 and 3.9)

• [ ] Refactor CI auto-release, testing this.

• [ ] Run periodic scans on schedule for Almalinux and the 2 CentOS 7:

  1. scan the image on registry.cern.ch
  2. report errors

[chokribr]

coordination: No PR associated @ntarocco shall we keep this tag in a progress status?

[ntarocco]

I hoped I have time to work on this, but at the moment I don't :( Let's put it back in to do :)