* Simplify docker systemd unit
systemd handles missing unit by ignoring the dependency so we don't need
to template them.
* Remove RHEL 7/CentOS 7 support
- remove ref in kubespray roles
- move CI from centos 7 to 8
- remove docs related to centos7
* Remove container-storage-setup
Only used for RHEL 7 and CentOS 7
* CI: reduce VM resources requests to improve scheduling
* CI: Reduce default jobs; add labels(ci-full/extended) to run more test
* CI: use jobs dependencies instead of stages
* precommit one-job
* CI: Use Kubevirt VM to run Molecule and Vagrant jobs
Max Gautier
ChengHao Yang
Antoine Legrand
Payback159