cfg: automatically create option groups
cfg: automatically create option groups

Implements blueprint cfg-auto-create-groups

Remove the restriction that groups must be explicitly created. Often
you only need a group to have a name (not e.g. a title or help string)
so we can easily just auto-create groups for that case.

Change-Id: I150ab3900e3aad0068b93487c8d396d21d26cfea

varunarya10/pbr,redhat-openstack/pbr,openstack-dev/pbr,emonty/oslo-packaging,citrix-openstack-build/pbr,varunarya10/pbr,klmitch/pbr,emonty/oslo-packaging,openstack-dev/pbr,openstack-dev/pbr,JioCloud/pbr,JioCloud/pbr,citrix-openstack-build/pbr,klmitch/pbr,redhat-openstack/pbr,WiFast/pbr,WiFast/pbr,citrix-openstack-build/pbr