The novaclient already has the following service commands:
service-disable Disable the service.
service-enable Enable the service.
service-list Show a list of all running services.
host-describe Describe a specific host
This covers what nova-manage service was providing so let's
deprecate the legacy nova-manage subcommand and mark it for
removal in the N release.
UpgradeImpact: nova-manage service is deprecated, use novaclient
DocImpact: update openstack operations guide
Implements: bp deprecate-service-management-in-nova-manage
Change-Id: I3e625dbf39f5831157104f5c368acd53b1899f76