To be able to filter on the address scope of the ports in the
ovn-bgp-agent we add the address scope of the subnet pool to
each LSP port in the northbound. Northd writes it to the
southbound so the ovn-bgp-agent has access to it. The
ovn-bgp-agent talks directly to the southbound to announce
the networks via BGP that match the configured address scope.
Change-Id: Ieb4cab11068747bd79868c6eb1778aab91447c30
Closes-Bug: #1996741
(cherry picked from commit 2272b9be95)
d64da06f74