added initial firewall check script in python

@lhicks @gvolz

To test, run: saltstack/srg/firewall/check-stig.pfsense.py --help

This will print out all the STIG rules.

srg/firewall/V-14637.py

@@ -13,6 +13,6 @@ import logging
 import util
 
 def run(xml_out):
-    findings = 'Unimplemented Rule'
-    return findings
+    f = util.Finding(util.UNIMPLEMENTED, 'Have not started yet')
+    return f