[Quality Assurance] Transition Stein to End of Life

As announced on mailing list [1], this patch transitions the Stein
branch to End of Life. The last patch of the branch will be tagged with
stein-eol tag. stable/stein branch cannot be used anymore and will be
deleted if this patch merges.

This is needed as stable/stein is not actively maintained in recent
period, thus gates are mostly broken due to job failures. Besides,
by removing these branches, infra resources will be freed up, too.

Please try to identify any zuul job, that is defined outside of the
repositories in this patch (for example in openstack-zuul-jobs, etc.)
and won't be used anymore if stable/stein is deleted. Propose a job
removal patch for them.

Please +1 if the team is ready for us to proceed with this transition,
or -1 if there are still some activity on the branch and the team wants
to continue to maintain it.

[1] https://lists.openstack.org/pipermail/openstack-discuss/2023-September/034965.html

Change-Id: I5deb2c0958fd0d49d32de93503a886af8ba3e429

deliverables/stein/devstack-plugin-amqp1.yaml

@@ -10,3 +10,8 @@ branches:
     name: stable/stein
 repository-settings:
   openstack/devstack-plugin-amqp1: {}
+releases:
+  - version: stein-eol
+    projects:
+      - repo: openstack/devstack-plugin-amqp1
+        hash: f40ac20c51595a45a95590d034a6909f4c5e8f5e

deliverables/stein/devstack-plugin-container.yaml

@@ -10,3 +10,8 @@ branches:
     name: stable/stein
 repository-settings:
   openstack/devstack-plugin-container: {}
+releases:
+  - version: stein-eol
+    projects:
+      - repo: openstack/devstack-plugin-container
+        hash: 541d79af779f66a1ce3df81f3e72f8a29b9570ec

deliverables/stein/devstack-plugin-kafka.yaml

@@ -10,3 +10,8 @@ branches:
     name: stable/stein
 repository-settings:
   openstack/devstack-plugin-kafka: {}
+releases:
+  - version: stein-eol
+    projects:
+      - repo: openstack/devstack-plugin-kafka
+        hash: 2b711840542981c7fec3cf044632945c20483cbe

deliverables/stein/devstack.yaml

@@ -10,3 +10,8 @@ branches:
     name: stable/stein
 repository-settings:
   openstack/devstack: {}
+releases:
+  - version: stein-eol
+    projects:
+      - repo: openstack/devstack
+        hash: 3021397dc82f05d1512065effd6dc908aa6c4838

deliverables/stein/grenade.yaml

@@ -10,3 +10,8 @@ branches:
     name: stable/stein
 repository-settings:
   openstack/grenade: {}
+releases:
+  - version: stein-eol
+    projects:
+      - repo: openstack/grenade
+        hash: 3d5fa687e38e511cc487fa18c298177b431522c5