Import firewall role from network repo

Move, actually.

roles/firewall/templates/firewall.intf.j2

@@ -0,0 +1,16 @@
+# disable IP forwarding on management interfaces
+{% for iface in interfaces | map(attribute="name") | select("match", "^mgmt[0-9]+") %}
+iface {{ iface }}
+    pre-up sysctl -w net.ipv4.conf.$IFACE.forwarding=0
+    pre-up sysctl -w net.ipv6.conf.$IFACE.forwarding=0
+
+{% endfor -%}
+
+# create VLANs 2 and 4 on firewal—exit links for inside and outside traffic
+{% for iface in interfaces | map(attribute="name") | select("match", "^lan")
+    | product([2, 4])
+    | map("join", ".") %}
+auto {{ iface }}
+iface {{ iface }}
+
+{% endfor %}