Use templates for cover and lower-constraints
Use templates for cover and lower-constraints

Small cleanups:

* Use openstack-tox-cover template, this runs the cover job
  in the check queue only. Remove individual cover jobs.
* Use openstack-lower-constraints-jobs template, remove individual
  jobs.
* Sort list of templates

Change-Id: I36081bfcc9e4cd393110c3fb6027048d57f925ad

openstack/ironic,openstack/ironic