testing: Add route-based/net2net-gre scenario

testing/tests/route-based/net2net-gre/hosts/sun/etc/strongswan.conf

@@ -0,0 +1,13 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 x509 revocation constraints pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce aes sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac vici kernel-netlink socket-default updown
+}
+
+charon {
+  install_routes = 0
+}