Use template for lower-constraints
Use template for lower-constraints

Small cleanups:

* Use openstack-lower-constraints-jobs template, remove individual
  jobs.
* Sort list of templates

Change-Id: I1131b423e890233af2fca3157640acaf0e803588
Needed-By: https://review.openstack.org/623229

openstack/murano-agent,openstack/murano-agent,openstack/murano-agent,openstack/murano-agent