TLS client & server: Support Encrypted Client Hello (ECH) (#3813)

https://github.com/XTLS/Xray-docs-next/commit/b9a72a4a26490cda4c915a857a78ce08ec273fe7

---------

Co-authored-by: yuhan6665 <1588741+yuhan6665@users.noreply.github.com>

transport/internet/tls/config.proto

@@ -91,4 +91,8 @@ message Config {
      @Critical
   */
   repeated string verify_peer_cert_in_names = 17;
+
+  string ech_config_list = 18;
+
+  bytes ech_server_keys = 19;
 }