ovn: Allow northd to install IPv6 ct_lb logical flows.
For this commit, ovn-northd will now accept both IPv4 and IPv6 addresses
in the northbound database for a load balancer VIP or destination
addresses. For IPv4, the behavior remains the same. For IPv6, the
following logical flows will be added to the southbound database:
* An ND_NA response for incoming ND_NS requests for the load balancer
VIP.
* A ct_lb flow with the configured IPv6 addresses.
The ovn-northd manpage has been updated to indicate what flows are
added for load balancers with IPv6 VIPs.
Signed-off-by: Mark Michelson <mmichels@redhat.com> Signed-off-by: Ben Pfaff <blp@ovn.org>