add iptables role and define firewall rules for mirror group

roles/base/tasks/RedHat.yml

@@ -32,3 +32,7 @@
     hour: 3
     minute: "{{ 59 | random(seed=inventory_hostname) }}"
     job: "yum -d 0 -e 0 -y --downloadonly update > /dev/null"
+
+- name: install os specific roles
+  include_role:
+    name: iptables