In order to be able to globally enable notification reporting for all services,
without an need to have ceilometer deployed or bunch of overrides for each
service, we add `oslomsg_notify_enabled` variable that aims to control
behaviour of enabled notifications.
Presence of ceilometer is still respected by default and being referenced.
Potential usecase are various billing panels that do rely on notifications
but do not require presence of Ceilometer.
This change also disables RPC communication for Glance since there's
no signs of RPC usage in Glance code. RabbitMQ seems to be used solely
for notifications
Depends-On: https://review.opendev.org/c/openstack/openstack-ansible-plugins/+/914144
Change-Id: I92b95acc5ec35468cafe041b277ef9fb3c21c2e4
1f4d83ef84