import zuul job settings from project-config

This is a mechanically generated patch to complete step 1 of moving
the zuul job settings out of project-config and into each project
repository.

Because there will be a separate patch on each branch, the branch
specifiers for branch-specific jobs have been removed.

See the python3-first goal document for details:
https://governance.openstack.org/tc/goals/stein/python3-first.html

Change-Id: I380e361d5687dcc7f79cada43c6c97e4ce5c9e98
Story: #2003250

.zuul.yaml

@@ -22,3 +22,11 @@
     gate:
       jobs:
         - openstack-tox-lower-constraints
+    templates:
+      - openstack-python-jobs
+      - openstack-python35-jobs
+      - publish-openstack-docs-pti
+      - check-requirements
+      - lib-forward-testing
+      - release-notes-jobs-python3
+      - periodic-stable-jobs