filter rules: interface list order changes on re-deploy

[zerwes]

as opnsense has it's own logic of sorting the interfaces in a filter rule, ansible run will re-deploy them and cause a diff, despite beeng the same list but just in a different order.
avoid diff's like

     - key: type
       value: pass
     - key: interface
-      value: i1,i2,i3
+      value: i2,i3,i1
     - key: ipprotocol
       value: inet
     - key: statetype

[zerwes]

fixed in #47