Provide a solution to emulate BM with libvirt

In order to provide a simple way to test sylva deployment on baremetal without too much infrastructure requirements, it would be great to provide a script to emulate baremetal servers with libvirt VMs managed by sushy library.

There are already several scripts out there that are performing that task, for example in metal3-dev-env, and also in kanod project (here and there)

As the current prerequisite to run Sylva is to install docker (in order to run kind bootstrap cluster) it would probably be relevant to build a container image that contains all the prerequisites (libvirt, sushy, as well as scripts and config files templates) and to start emulated VMs within these containers. This could be helpfull to limit dependency and impact on the host on which these emulated hosts are spawned.