introduce OvsNetworkTopologyGuru that has convinenace functions to
   - get the hosts on which VPC spans given vpc id
   - get the VM's in the VPC
   - get the hosts on which a network spans
   - get the VPC's to which a hosts is part of
   - get VM's of a VPC on a hosts

introduces capability to build a physical toplogy representation of a
VPC. This json file is encapsulated in
OvsVpcPhysicalTopologyConfigCommand, and is used to send full topology
to hypervisor hosts. On hypervisor this json config can be used to setup
tunnels, configure bridge, add flow rules etc

Ovs GURU, to use different broasdcast scheme VS://vpcid.gerkey for the
networks in VPC that use distributed routing

each VIF and tunnel interface to carry the network UUID in other/options
config