testing: Added ikev2/net2net-multicast scenario

testing/tests/ikev2/net2net-multicast/hosts/sun/etc/strongswan.conf

@@ -0,0 +1,13 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+charon {
+  load = aes des sha1 sha2 pem pkcs1 gmp random nonce x509 curl revocation hmac stroke kernel-netlink socket-default forecast
+
+  multiple_authentication = no
+  plugins {
+    forecast {
+      groups = 224.0.0.251
+      interface = eth1
+    }
+  }
+}