RHEL8 Image Updates for Kubevirt Fencing

We will need certain packages to be included in the RHEL 8 image used for the overcloud, for the purpose of supporting Kubevirt VM fencing via Pacemaker.  These include:

1. A package for the Kubevirt agent Python binary itself (either include the agent in the "all fencing agents" RPM or install it via its own RPM)
2. python-openshift v0.12.1 (a dependency of the Kubevirt agent)
3. Updates to the `puppet-tripleo` package to recognize "fence_kubevirt" as a valid fencing option
4. A new file in `puppet-pacemaker` to represent the "fence_kubevirt" Puppet module itself