feat(config): add search_domains with "cm.cluster"

Added the `search_domains` variable to group_vars/prod

ansible/group_vars/prod

 ---
+  search_domains:
+  - "cm.cluster"
+
   hostname_lookup_table:
     - "172.20.0.24 cheaha-master02.cm.cluster cheaha-master02"
     - "172.20.0.22 cheaha-master01.cm.cluster cheaha-master01"