commands: add cluster-naming to create cluster with better naming

When using cluster-naming the hosted-vm belonging to the cluster
will be named with
vm-FEName-ID
so that their name will be indipendend from the physical container
they are allocated.
This should make easier to read rocks list host as well.
command: fix minor bug with charon
commands: set host vm cdrom: do not check if the file exists

maybe the ISO does not exist when set but it will exist when the
VM is booted. For the moment do not check os.path.exists
commands: airboss: added cdrom remote operation to set ISO path