Use Zuul templates

Use templates instead of individual jobs so that these
can be changed in one place.

Depends-On: https://review.opendev.org/677606
Change-Id: I1b81f71977bcaa52e60566b9a64bffe6ffdab7d6

.zuul.yaml

@@ -1,11 +1,11 @@
 ---
 - project:
     templates:
-      - build-openstack-docs-pti
+      - publish-stx-docs
+      - stx-api-ref-jobs
+      - stx-release-notes-jobs
     check:
       jobs:
-        - build-openstack-api-ref
-        - build-openstack-releasenotes
         - flock-devstack-nfv
         - openstack-tox-linters
         - nfv-tox-pep8
@@ -16,8 +16,6 @@
         - nova-api-proxy-tox-pylint
     gate:
       jobs:
-        - build-openstack-api-ref
-        - build-openstack-releasenotes
         - flock-devstack-nfv
         - openstack-tox-linters
         - nfv-tox-pep8
@@ -26,11 +24,6 @@
         - nfv-tox-pylint
         - nova-api-proxy-tox-pep8
         - nova-api-proxy-tox-pylint
-    post:
-      jobs:
-        - publish-stx-api-ref
-        - publish-stx-tox
-        - publish-stx-releasenotes
 
 - job:
     name: nfv-tox-py27