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: I20f5a43bc6ff5b2bea7ec4c9c00526dd9d8e5a19
Needed-By: https://review.openstack.org/623229

openstack/blazar,ChameleonCloud/blazar,stackforge/blazar,stackforge/blazar,ChameleonCloud/blazar,openstack/blazar