monkey patch QuantumDbPluginV2 _generate_ip/mac

This works around the lack of a plugable IP generation scheme in Quantum
ensure that router ports are properly attached

NVP normally does not attached these kinds of ports, but for Akanda
these ports need to be attached.
Add additional comments to provide context.
adds wraps to _generate_ wrappers
Merge pull request #5 from markmcclain/deco_fix

monkey patch QuantumDbPluginV2 _generate_ip/mac