Add `openshift_node_open_ports` to allow arbitrary firewall exposure

It should be possible for an admin to define an arbitrary set of ports
to be exposed on each node that will relate to the cluster function.
This adds a new global variable for the node that supports

    Array(Object{'service':<name>,'port':<port_spec>,'cond':<boolean>})

which is the same format accepted by the firewall role.

roles/openshift_node/defaults/main.yml

@@ -60,7 +60,7 @@ openshift_deployment_type: origin
 openshift_node_bootstrap: False
 
 r_openshift_node_os_firewall_deny: []
-r_openshift_node_os_firewall_allow:
+default_r_openshift_node_os_firewall_allow:
 - service: Kubernetes kubelet
   port: 10250/tcp
 - service: http
@@ -79,6 +79,8 @@ r_openshift_node_os_firewall_allow:
 - service: Kubernetes service NodePort UDP
   port: "{{ openshift_node_port_range | default('') }}/udp"
   cond: "{{ openshift_node_port_range is defined }}"
+# Allow multiple port ranges to be added to the role
+r_openshift_node_os_firewall_allow: "{{ default_r_openshift_node_os_firewall_allow | union(openshift_node_open_ports | default([])) }}"
 
 oreg_url: ''
 oreg_host: "{{ oreg_url.split('/')[0] if '.' in oreg_url.split('/')[0] else '' }}"