fix: windows crashes & builds (#55)

- Doing jobs in parallels in GHA (Divide build time by 3).
- Now use custom webrtc builds for this repo
- Windows crashes when receiving video is now fixed (thanks @cloudwebrtc)
    - Now reading defines from webrtc.ninja
- Added a small create_pc test to be sure libwebrtc is working/linked correctly 
- Fix MacOS builds 
- Fixed Linux duplicated main build error (due to nasm)

livekit-webrtc/src/native/peer_connection.rs

@@ -110,6 +110,7 @@ impl From<sys_pc::ffi::SignalingState> for SignalingState {
 
 #[derive(Clone)]
 pub struct PeerConnection {
+    #[allow(dead_code)]
     native_observer: SharedPtr<sys_pc::ffi::NativePeerConnectionObserver>,
     observer: Arc<PeerObserver>,
 

livekit-webrtc/src/native/rtp_parameters.rs

@@ -1,5 +1,4 @@
 use crate::rtp_parameters::*;
-use crate::MediaType;
 use webrtc_sys::rtp_parameters as sys_rp;
 use webrtc_sys::webrtc as sys_webrtc;
 

livekit-webrtc/src/native/rtp_transceiver.rs

@@ -5,7 +5,6 @@ use crate::rtp_receiver;
 use crate::rtp_sender;
 use crate::rtp_transceiver::RtpTransceiverDirection;
 use crate::rtp_transceiver::RtpTransceiverInit;
-use crate::MediaType;
 use crate::RtcError;
 use cxx::SharedPtr;
 use webrtc_sys::rtc_error as sys_err;
@@ -33,7 +32,6 @@ impl From<RtpTransceiverDirection> for sys_webrtc::ffi::RtpTransceiverDirection
             RtpTransceiverDirection::RecvOnly => Self::RecvOnly,
             RtpTransceiverDirection::Inactive => Self::Inactive,
             RtpTransceiverDirection::Stopped => Self::Stopped,
-            _ => panic!("unknown RtpTransceiverDirection"),
         }
     }
 }