This commit adds simple roles to manage:
- libvirt service, domains, volumes, networks and pools.
- redfish-emulator role installs sushy-tools from pip, together
with support packages
Please note, that libvirt roles are not meant to be completely
idempotent, their main job is deploy temporary resources that for
ci and gating purposes, to be tore down afterwards. Roles are
specifically made to be simple to debug, and don't contain any
complex logic to make them portable, flexible or idempotent.