[RFE] Add physical network awareness to hash ring placement

There are several scenarios where affinity between baremetal nodes and ironic conductors is important.

An example of this is in a spine and leaf L3 network scenario, where baremetal nodes live in separated L2 leafs of the larger L3 network. In these scenario's its advantageous to also have the Ironic conductors managing those baremetals to be in the same leaf.

There is currently no way to influence the Ironic node to conductor placement outside of which driver a node is configured with and which drivers an conductor has enabled.

This RFE is proposing extending the information used by Ironic to calculate the hash ring placement to include which "physical networks" the conductor has access too, where "physical network" is has the same meaning as in the network service or on ironic ports, separate physical L2 infrastructure.

A real world example of this is in a spine and leaf network a physical network refers to the leaf that a conductor or baremetal node is directly plugged into.

There are a few changes required to allow this information to be used by the hash ring,

1. we need to provide a configuration option in the conductor to make it aware of which physical networks it is connected to.

2. we need to modify the hash ring placement code to take into account the physical networks from the conductor and from the node *IF* it has port's with physical network information.

2. we need to modify the node port create/update logic to trigger a re-balance of the hash ring when physical network information is provided or changed for a node.