testing: Add DSCP scenario that uses simple labels

Instead of creating two IKE_SAs with different identities, this scenario
uses simple labels to select the correct child config.

testing/tests/ikev2/net2net-dscp/hosts/moon/etc/strongswan.conf

@@ -0,0 +1,14 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 x509 revocation constraints pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce aes sha1 sha2 hmac pem pkcs1 x509 revocation curve25519 gmp curl kernel-netlink socket-default updown vici
+  syslog {
+    daemon {
+      knl = 2
+    }
+  }
+}