DHC-1456 Update Akanda/Neutron plugins for Havana

DHC-1456

In order to make the RUG working with havana, we need to change
all the references from quantum to neutron

Change-Id: I127ff788f61d55ca12d9da1f2f149c0e2e4ccff1
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>