[train] Switch to content provider jobs/templates

This change switches templates and jobs to the content provider
dependency relation so the jobs share the produced artifacts.

Change-Id: Ie88e4e8f0d61c9e847e5441cc301fb42a90c92c1

zuul.d/layout.yaml

@@ -1,6 +1,6 @@
 - project:
     templates:
-      - tripleo-multinode-container-minimal
+      - tripleo-multinode-container-minimal-pipeline
       - openstack-python3-train-jobs
       - check-requirements
       - publish-openstack-docs-pti