Use Koan instead of own Virtualization Code #300
Description
Currently, Orthos implements its own virtualization management. To slowly work towards the goal of #219 of deprecating this project, I would like to propose using Koan to manage the installation of virtual machines. This would reduce the amount of code inside Orthos 2 by ~1k lines.
The tricky part here is that we need to remove the vm_* fields in machine.py that are not needed anymore. Also, Cobbler needs potentially be made aware that the added machine is a VM.