Add rhosp-release rpm in rhel images

Currently, In RHOSP17: task[1] fails while installing rpm if overcloud
nodes don't have repos.
It is expected that overcloud node contain all required things
with image build.

[1] https://opendev.org/openstack/tripleo-ansible/src/branch/master/tripleo_ansible/roles/tripleo_bootstrap/tasks/main.yml#L39
Related-Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1954108

Change-Id: Ie14e58c999210760170d01c1873883d423fe4ada

image-yaml/overcloud-hardened-images-rhel8.yaml

@@ -7,3 +7,5 @@ disk_images:
       DIB_RELEASE: '8'
     elements:
       - interface-names
+    packages:
+      - rhosp-release

image-yaml/overcloud-hardened-images-uefi-rhel8.yaml

@@ -7,4 +7,5 @@ disk_images:
       DIB_RELEASE: '8'
     elements:
       - interface-names
-
+    packages:
+      - rhosp-release

image-yaml/overcloud-images-ceph-rhel8.yaml

@@ -6,3 +6,5 @@ disk_images:
     release: 8
     elements:
       - interface-names
+    packages:
+      - rhosp-release

image-yaml/overcloud-images-rhel8.yaml

@@ -7,6 +7,8 @@ disk_images:
     elements:
       - selinux-permissive
       - interface-names
+    packages:
+      - rhosp-release
     environment:
       FS_TYPE: xfs
     options: