fix: cgred update for rhel8

[gonzaloetjo]

Which issue(s) this PR fixes

Fixes #71

Additional comments

cgrep has been depreciated in favor of systemd for rhel8 or any 8.x derivative rpm -q --changelog libcgroup. :

Tue Jan 14 2014 … 0.41-1

    resolves: #966008
    updated to 0.41
    removed deprecated cgred service
    please use Control Group Interface in Systemd instead

source: http://rpmfind.net/linux/RPM/centos/8-stream/baseos/x86_64/Packages/libcgroup-0.41-19.el8.x86_64.html

Agreements

• [x] I hereby declare this contribution to be licensed under the Apache License Version 2.0, January 2004.
• [x] I hereby agree to grant TOSIT a copyright license to use my contributions.

[PACordonnier]

Lets have a discussion about whether or not we start to drop RHEL7 support altogether for prerequisites 0.2/ I think no one is really interested in rhel 7 anymore and someone could always do some work from 0.1.

I'm not saying we should delete the existing code that manages rhel7/8 differences, but I think we can consider not adding more and focus on rhel8.

This PR relates to https://github.com/TOSIT-IO/tdp-collection-prerequisites/pull/87 and https://github.com/TOSIT-IO/tdp-vagrant/pull/22