At the moment the only way to configure multi-AZ support in Neutron were
config overrides, which work quite nicely with LXB/OVS scenarios. However,
with OVN changing configuration is not enough, and command that sets
up OVN Gateway should provide extra CMS option.
In order to improve AZ support in Neutron role, we add couple of variables
that control behaviour and allow to perform required configuration without
config overrides for OVS/LXB/OVN.
Co-Authored-By: Danila Balagansky <dbalagansky@me.com>
Closes-Bug: #2002040
Change-Id: Ic964329c06765176692f7b0c32f33ec46360a3fb