[Quality Assurance] Transition Zed to Unmaintained

This branch reached the end of its official stable maintained period,
hence this patch transition stable/zed branch to Unmaintained. (For
details about Unmaintained state please see: [1][2])

The transitions is as follows:
- tip of the stable/zed branch is tagged with zed-eom tag
- unmaintained/zed branch will be cut from zed-eom tag
- stable/zed branch will be deleted

Note:
- there will no longer be official releases off of zed branch after this
  transition
- backports can be pushed to unmaintained/zed branch
- openstack-unmaintained-core (or <project>-unmaintained-core groups if
  such exists) have the rights to merge patches

Important: please +1 if the team is ready for us to proceed with this
transition, or -1 if there are any final Zed stable release with
backports currently in flight that we should wait for. For the latter
case, please propose a final Zed stable release patch, and rebase this
patch on top of that, with the latest commit hash of stable/zed.

The transition deadline is May 2nd, 2024. [3]

[1] https://docs.openstack.org/project-team-guide/stable-branches.html#unmaintained
[2] https://governance.openstack.org/tc/resolutions/20230724-unmaintained-branches.html
[3] https://releases.openstack.org

Change-Id: Ie6a0034451fa7d6a2616129c99c2783f315f467c

deliverables/zed/devstack-plugin-ceph.yaml

@@ -8,5 +8,12 @@ branches:
   - location:
       openstack/devstack-plugin-ceph: 46186d062b1ef3d93385344140632dcebb665784
     name: stable/zed
+  - name: unmaintained/zed
+    location: zed-eom
 repository-settings:
   openstack/devstack-plugin-ceph: {}
+releases:
+  - version: zed-eom
+    projects:
+      - repo: openstack/devstack-plugin-ceph
+        hash: f6aebfc076b9e51ab4a33d4f5727267589227ac7

deliverables/zed/devstack-plugin-container.yaml

@@ -8,5 +8,12 @@ branches:
   - location:
       openstack/devstack-plugin-container: b323f5b71a17ce17de4cff2b01742bf322063d26
     name: stable/zed
+  - name: unmaintained/zed
+    location: zed-eom
 repository-settings:
   openstack/devstack-plugin-container: {}
+releases:
+  - version: zed-eom
+    projects:
+      - repo: openstack/devstack-plugin-container
+        hash: 7fc56c721c1e4cb470192cf6f3f953ccc59e0d33

deliverables/zed/devstack.yaml

@@ -8,5 +8,12 @@ branches:
   - location:
       openstack/devstack: 0b0e6a647477131b5953858b3eed3d463412779f
     name: stable/zed
+  - name: unmaintained/zed
+    location: zed-eom
 repository-settings:
   openstack/devstack: {}
+releases:
+  - version: zed-eom
+    projects:
+      - repo: openstack/devstack
+        hash: 1183167f191923f2473f1a93fece4caf8df2be54

deliverables/zed/grenade.yaml

@@ -8,5 +8,12 @@ branches:
   - location:
       openstack/grenade: 793f553bddfb74394f9d98eb5f1618b0caf2f9c3
     name: stable/zed
+  - name: unmaintained/zed
+    location: zed-eom
 repository-settings:
   openstack/grenade: {}
+releases:
+  - version: zed-eom
+    projects:
+      - repo: openstack/grenade
+        hash: 9e28c1dcbae58565ecb29fdb8d2234b94f24f779