[ci] Add support for RHEL 7 and 8

[pandafy]

The role already contains tasks for installing everything on RHEL 7 and 8. It has also been manually tested on those systems. There is need to add CI builds for these distribution.

[DarshiniKurasa]

Hey @pandafy, I want to take this one.

I’m going to expand our CI coverage to include RHEL 7 and 8. I’ll do that by adding CentOS 7 and Rocky Linux 8 to the CI matrix, those are the go-to community versions for Molecule and Ansible tests. No changes to the role’s logic, just better coverage in CI.

Once I’ve got the updates ready, I’ll open a PR. Thanks!