testing: Add pfkey/shunt-policies-nat-rw scenario

testing/tests/pfkey/shunt-policies-nat-rw/hosts/sun/etc/ipsec.conf

@@ -0,0 +1,20 @@
+# /etc/ipsec.conf - strongSwan IPsec configuration file
+
+config setup
+
+conn %default
+	ikelifetime=60m
+	keylife=20m
+	rekeymargin=3m
+	keyingtries=1
+	keyexchange=ikev2
+
+conn nat-t
+	left=PH_IP_SUN
+	leftcert=sunCert.pem
+	leftid=@sun.strongswan.org
+	leftfirewall=yes
+	leftsubnet=0.0.0.0/0
+	right=%any
+	rightsourceip=10.3.0.0/28
+	auto=add