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: I76d801da15904142bda0503c5bfa9f11b4ea84f1

.zuul.yaml

@@ -268,6 +268,8 @@
 
 - project:
     templates:
+      - openstack-cover-jobs
+      - openstack-lower-constraints-jobs
       - publish-openstack-docs-pti
       - periodic-stable-jobs
       - check-requirements
@@ -378,7 +380,6 @@
               - ^(api-ref|doc|releasenotes)/.*$
               - ^test/probe/.*$
               - ^(.gitreview|.mailmap|AUTHORS|CHANGELOG)$
-        - openstack-tox-lower-constraints
         - openstack-tox-pep8:
             irrelevant-files:
               - ^(api-ref|etc|examples|releasenotes)/.*$
@@ -394,5 +395,4 @@
 
     post:
       jobs:
-        - openstack-tox-cover
         - publish-openstack-python-branch-tarball