CloudLinux recognition in Red Hat 8

[Firaell]

This PR is an attempt to fix # by .

Checklist

• based on top of latest source code
• changelog entry included
• tests pass in CI
• git history is clean
• git commit messages are well-written

[ferki]

Thanks for your contribution!

This PR does not fully follow the project's expectations, so I'd like to take this chance to kindly link our Contributing guide, specifically the section about GitHub issues and pull requests.

Please follow the pull request template to provide all expected information either by editing the opening post here, or by opening a new pull request instead of this one.

---

I've downloaded a CloudLinux qcow2 image and started up a local VM with it. Rex got it recognized as Red Hat (due to the presence of the /etc/redhat-release file).

That means Rex already picks up the correct Rex::Pkg::Redhat module to manage packages, and the correct Rex::Service::Redhat::systemd module to manage services on CloudLinux. is_redhat() also recognizes it correctly as a Red Hat variant (returns 1), so there's no need to add it to the list of Red Hat clones.

In other words, Rex should already support CloudLinux without any further changes 🎉

So I wondered what do we exactly try to solve here? I would like to learn more about the problem we solve or the new capability we need to add. I'd say it's best to do that via a separate issue (for discussion and design of potential implementations).

Apart from that, we'd need to add a changelog entry here, and run the tests. These steps were checked in the otherwise untouched template, so I'll remove the check for now.