Add publish-to-pypi-quietly project-template

There are some things that want to release to PyPI but do not want to
generate OpenStack release emails or upper-constraints bumps. Make a
template for them too.

While we're in here, add a description to publish-to-pypi as well.

Change-Id: I75850f8f6e3a4b7eb796afa4f5ea947dfce347f8

zuul.yaml

@@ -58,6 +58,9 @@
 
 - project-template:
     name: publish-to-pypi
+    description: |
+      Publish a Python package to PyPI, then send release announcement
+      emails and propose updates to upper-constraints as needed.
     pre-release:
       jobs:
         - publish-openstack-python-tarball
@@ -77,6 +80,18 @@
             dependencies:
               - publish-openstack-python-tarball
 
+- project-template:
+    name: publish-to-pypi-quietly
+    description: |
+      Publish a Python package to PyPI but do not send announce emails or
+      propose upper-constraints updates.
+    pre-release:
+      jobs:
+        - publish-openstack-python-tarball
+    release:
+      jobs:
+        - publish-openstack-python-tarball
+
 - project-template:
     name: openstack-python-jobs
     check: