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.

Because this patch is generated by a script, there may be some
cosmetic changes to the layout of the YAML file(s) as the contents
are normalized.

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

Change-Id: Id3d18f3c30ed3afde34bda917aca9e6d2c89505f

.zuul.yaml

@@ -1,9 +1,8 @@
 - project:
     templates:
       - openstack-specs-jobs
-    check:
-      jobs:
-        - openstack-tox-py27
-    gate:
-      jobs:
-        - openstack-tox-py27
+      - openstack-python-jobs
+      - openstack-python35-jobs
+      - openstack-python36-jobs
+      - publish-openstack-docs-pti
+      - check-requirements