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

Use openstack-tox-cover template, this runs the cover job as
non-voting in the check queue only.

Use openstack-lower-constraints-jobs template

Remove jobs that are part of the templates.

Change-Id: I0217788b2031eeb05e74e89225db32f503f15c62

openstack/python-saharaclient