ci: testing farm tests now use 5 managed nodes [citest_skip]

snapshot needs another managed node to speed up testing

Author: richm

plans/test_playbooks_parallel.fmf

@@ -13,6 +13,8 @@ provision:
     role: managed_node
   - name: managed-node4
     role: managed_node
+  - name: managed-node5
+    role: managed_node
 environment:
   # ensure versions are strings!
   SR_ANSIBLE_VER: "2.17"