feat: 增加webrtc代理拉流 (#4389)

- 增加客户端模式，支持主动拉流、推流：
   - addStreamProxy接口新增支持whep主动拉流，拉流地址目前只兼容zlm的whep url。
   - addStreamPusherProxy接口新增支持whip主动推流，推流地址目前只兼容zlm的whip url。
   - 以上推流url格式为webrtc[s]://server_host:server_port/app/stream_id?key=value, 内部会自动转换为http[s]://server_host:server_port/index/api/[whip/whep]?app=app&stream=stream_id&key=value。

- 增加WebRtc p2p 模式：
  - 增加 ICE FULL模式。
  - 增加STUN/TURN 服务器。
  - 增加websocket 信令。
  - 增加P2P代理拉流。

---------

Co-authored-by: xia-chu <771730766@qq.com>
Co-authored-by: mtdxc <mtdxc@126.com>
Co-authored-by: cqm <cqm@97kid.com>

webrtc/WebRtcSignalingMsg.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
+ *
+ * This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
+ *
+ * Use of this source code is governed by MIT-like license that can be found in the
+ * LICENSE file in the root of the source tree. All contributing project authors
+ * may be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#ifndef ZLMEDIAKIT_WEBRTC_SIGNALING_MSG_H
+#define ZLMEDIAKIT_WEBRTC_SIGNALING_MSG_H
+
+#include "server/WebApi.h"
+
+namespace mediakit {
+namespace Rtc {
+
+#define SIGNALING_MSG_ARGS const HttpAllArgs<Json::Value>& allArgs
+
+// WebRTC 信令消息键名和值常量声明
+extern const char* const CLASS_KEY;
+extern const char* const CLASS_VALUE_REQUEST;
+extern const char* const CLASS_VALUE_INDICATION;        // 指示类型,不需要应答
+extern const char* const CLASS_VALUE_ACCEPT;            // 作为CLASS_VALUE_REQUEST的应答
+extern const char* const CLASS_VALUE_REJECT;            // 作为CLASS_VALUE_REQUEST的应答
+extern const char* const METHOD_KEY;
+extern const char* const METHOD_VALUE_REGISTER;         // 注册
+extern const char* const METHOD_VALUE_UNREGISTER;       // 注销
+extern const char* const METHOD_VALUE_CALL;             // 呼叫(取流或推流)
+
+extern const char* const METHOD_VALUE_BYE;              //  挂断
+extern const char* const METHOD_VALUE_CANDIDATE;
+extern const char* const TRANSACTION_ID_KEY;            // 消息id,每条消息拥有一个唯一的id
+extern const char* const ROOM_ID_KEY;
+extern const char* const GUEST_ID_KEY;                 // 每个独立的会话，会拥有一个唯一的guest_id
+extern const char* const SENDER_KEY;
+extern const char* const TYPE_KEY;
+extern const char* const TYPE_VALUE_PLAY;              // 拉流
+extern const char* const TYPE_VALUE_PUSH;              // 推流
+extern const char* const REASON_KEY;
+extern const char* const CALL_VHOST_KEY;
+extern const char* const CALL_APP_KEY;
+extern const char* const CALL_STREAM_KEY;
+extern const char* const SDP_KEY;
+
+extern const char* const ICE_SERVERS_KEY;
+extern const char* const CANDIDATE_KEY;
+extern const char* const URL_KEY;
+extern const char* const UFRAG_KEY;
+extern const char* const PWD_KEY;
+
+} // namespace Rtc
+} // namespace mediakit
+//
+
+#endif //ZLMEDIAKIT_WEBRTC_SIGNALING_PEER_H