Move retired.config to external namespace

The retired.config is aimed for all tenants of OpenDev, there's no need
for it to live inside OpenStack.

Change-Id: I98cffdb966548544b53cf367d5048c5a2503f060

dev/gerrit/projects.yaml

@@ -5,7 +5,7 @@
 - project: gtest-org/test2
 - project: gtest-org/test3
 - project: gtest-org/test-deb-alembic
-  acl-config: /home/gerrit2/acls/openstack/retired.config
+  acl-config: /home/gerrit2/acls/opendev/retired.config
 - project: gtest-org/test-manage-project
   acl-config: /home/gerrit2/acls/test-manage-project.config
 - project: gtest-org/test.hyphen