Allow import of VMs connected to an overlay network with IPAM. This includes:

1. Specifying the IP address of the VM for OVNK to use (but not assign) via persistent IP or some other mechanism
2. Detect/expose the MAC for the VM to be configured in OVNK for the VM
3. When creating the UDN, be able to specify the gateway IP address, so the migrated VM can keep the same default route.
4. Support unNATed ingress/egress for VMs when using BGP(limited to cluster UDNs)
5.  [TBD] When creating the UDN, allow excludeSubnets to be used with L2 UDNs to ensure OVNK does not use an IP address from the range that VMs have already been assigned outside of the cluster.

Slack channel: #udn-cnv-sdn-static-ips

Why is this important?

Some users are running VMs in virtualization platforms having a managed IP configuration.

For this kind of users, we need to have a way to enable their existing VMs to run properly after being migrated into OpenShift, without any guest configuration changes.

For that, we need to import the VMs from their existing platforms, preserving their existing MACs, IPs, and gateway configuration.