RtpTransceiver bindings & requirements for publishing tracks (#39)

- RtpSender
- RtpReceiver
- RtpTransceiver
- RtpParameters
- VideoFrameBuilder
- Interior mutability on c++ side
- Cleanup bindings ( Use #pragma once instead of include guards )
     - webrtc-sys/src/* headers are now used in only one place 
     - Avoid confusion between generated headers and our headers
- AdaptedVideoTrackSource
- Cleanup the workaround with unsupported Vec<Shared<T>>
    - Put everything inside one file

webrtc-sys/include/livekit/webrtc.h

@@ -2,8 +2,7 @@
 // Created by theom on 18/09/2022.
 //
 
-#ifndef LIVEKIT_WEBRTC_WEBRTC_H
-#define LIVEKIT_WEBRTC_WEBRTC_H
+#pragma once
 
 #include "rtc_base/physical_socket_server.h"
 #include "rtc_base/ssl_adapter.h"
@@ -12,6 +11,11 @@
 #include "rtc_base/win32_socket_init.h"
 #endif
 
+namespace livekit {
+class RTCRuntime;
+}
+#include "webrtc-sys/src/webrtc.rs.h"
+
 namespace livekit {
 
 class RTCRuntime {
@@ -30,15 +34,14 @@ class RTCRuntime {
   std::unique_ptr<rtc::Thread> network_thread_;
   std::unique_ptr<rtc::Thread> worker_thread_;
   std::unique_ptr<rtc::Thread> signaling_thread_;
+
 #ifdef WEBRTC_WIN
   rtc::WinsockInitializer winsock_;
   rtc::PhysicalSocketServer ss_;
-  rtc::AutoSocketServerThread main_thread_ {&ss_};
+  rtc::AutoSocketServerThread main_thread_{&ss_};
 #endif
 };
 
 std::shared_ptr<RTCRuntime> create_rtc_runtime();
 
 }  // namespace livekit
-
-#endif  // LIVEKIT_WEBRTC_WEBRTC_H