Add and use a deploy pipeline

This is independent + change-merged. With files matchers, promote
is actually problematic because we'd elide sets of different
changes potentially missing triggers.

Use deploy pipeline for project-config deployments

These all have files matchers which makes using them in promote
problematic due to deduplication.

Change-Id: Ic77cdb2aab359b20b9c8b3a66ee031d24f7c95a0

zuul.d/pipelines.yaml

@@ -194,6 +194,28 @@
     failure:
       mysql:
 
+- pipeline:
+    name: deploy
+    description: |
+      This pipeline runs jobs that operate after each change is merged
+      in order to run production deployment playbooks.
+    success-message: Build succeeded (deploy pipeline).
+    failure-message: |
+      Build failed (deploy pipeline).  For information on how to proceed, see
+      https://docs.opendev.org/opendev/infra-manual/latest/developers.html#automated-testing
+    manager: independent
+    precedence: high
+    post-review: True
+    trigger:
+      gerrit:
+        - event: change-merged
+    success:
+      gerrit: {}
+      mysql:
+    failure:
+      gerrit: {}
+      mysql:
+
 - pipeline:
     name: opendev-prod-hourly
     post-review: true

zuul.d/projects.yaml

@@ -3318,7 +3318,7 @@
         - project-config-bindep-fallback-centos-7
         - project-config-bindep-fallback-opensuse-15
         - project-config-bindep-fallback-ubuntu-xenial
-    promote:
+    deploy:
       jobs:
         - promote-infra-index:
             files: *infra-docs-index