[PowerVMStackers] Transition Stein to EM

This transition the stein branch to extended maintenance.
Changes for bugfixes and things the team deems important are
still encouraged, but there will no longer be official releases
off of the branch.

Please +1 if the team is ready for us to proceed with this
transition, or -1 if there are any final backports currently in
flight that we should wait for. For the latter case, please
update the patch with the new commit hash after doing a final
release to get those changes out so we know to proceed with the
transition.

Change-Id: I5cdd8b2c7e1308302059af39de9f976f69a44a4d

deliverables/stein/ceilometer-powervm.yaml

@@ -20,5 +20,9 @@ releases:
       - repo: openstack/ceilometer-powervm
         hash: 4acc295bb0e6c60c5a9dca8516782cdd98e7c12b
     version: 8.0.0
+  - version: stein-em
+    projects:
+      - repo: openstack/ceilometer-powervm
+        hash: 4acc295bb0e6c60c5a9dca8516782cdd98e7c12b
 repository-settings:
   openstack/ceilometer-powervm: {}

deliverables/stein/networking-powervm.yaml

@@ -20,5 +20,9 @@ releases:
       - repo: openstack/networking-powervm
         hash: 27610e36de0e2f65f5b7d9064d6a6f2ef1f480c4
     version: 8.0.0
+  - version: stein-em
+    projects:
+      - repo: openstack/networking-powervm
+        hash: 27610e36de0e2f65f5b7d9064d6a6f2ef1f480c4
 repository-settings:
   openstack/networking-powervm: {}

deliverables/stein/nova-powervm.yaml

@@ -20,6 +20,10 @@ releases:
       - repo: openstack/nova-powervm
         hash: dbcf3ff41ba25e17c6caf7e76e0f5876c2038c29
     version: 8.0.0
+  - version: stein-em
+    projects:
+      - repo: openstack/nova-powervm
+        hash: dbcf3ff41ba25e17c6caf7e76e0f5876c2038c29
 repository-settings:
   openstack/nova-powervm:
     tarball-base: nova_powervm