Add verify_ports to agent verification

Listens for LLDP info on all interfaces, then attempts to match that to
the ports Ironic has, raising Verification errors if they don't match up.

Relies on https://review.openstack.org/#/c/92627/ for LLDP tools in the Agent.
When I was first writing this code, this was going in the upstream agent. I still want some of this to move over, but the TLV parsing is going to be switch specific. But then again, this shit should be in the port objects anyway, rather than some silly extra key.