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

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

Use openstack-lower-constraints-jobs template.

Remove jobs that are part of the templates.

Change-Id: I168feb6c304cf14efe06e6d8f3726facc1c3c7b4

openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib