[FN VMs] remove graphics

[FN VMs] remove graphics

Since VCP VMs (created via salt formula) do not have a video
controller defined in their domain XMLs, network devices end on
different PCI slots and hence have different names assigned
(ens2+ vs foundation node VMs, which start with ens3).

To align network interface names for VMs on jumpserver vs kvm nodes,
and reduce confusion, remove the video controller from FN VMs.

This allows some cleanup:
- drop extra AArch64 args from virt-install;
- unify 'opnfv_vcp_vm_*' and 'opnfv_fn_vm_*' variables;

Change-Id: I0d108b00914b3eaaa03b67c652174f8ed4573118
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>