[baremetal] Retire mas01 NAT

[baremetal] Retire mas01 NAT

Isolate networks by retiring NAT on mas01; also cutting direct
internet access from cluster nodes that are not facing the public
network (prx, cmp).

NOTE: Since we are removing mas01 NAT, VCP VMs (except prx which have
public IPs) and kvm nodes (cmp also have public IPs) will no longer
have direct internet connectivity.
Cluster deployment and operations will work without it, but if it is
required for different reasons, the MaaS proxy could be enabled by
uncommenting the /etc/enviroment section in:
- cluster.baremetal-mcp-pike-common-ha.include.proxy.yml

JIRA: FUEL-317

Change-Id: I5ed8b420296b27df34a54ec1ebd7b7cf58041425
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
(cherry picked from commit 9a6e655e0b851ff6e449027c01ac1a66188b0064)