Fix race conditions by switching to node webcrypto

[koush]

builds on top of https://github.com/shinyoshiaki/werift-webrtc/pull/395

certificate creation is async now, so the setupCertificate method needs to handle double calls correctly.

the main issue that was uncovered is that localDescription is now undefined when ice candidate gathering starts.

The underlying issue is that ice candidate gathering is being started during a setRemoteDescription offer. Werift (the answer peer) has not created an answer or called setLocalDescription at this point. But it has started gathering peers based on the offer side description.

https://github.com/shinyoshiaki/werift-webrtc/blob/18b4194c271410da132000e9e460424a6c8cc3f5/packages/webrtc/src/peerConnection.ts#L1000-L1012

I believe this behavior is incorrect. Ice candidate gathering should only ever start during createAnswer and createOffer (or possibly setLocalDescription), as that is the typical spec/implementation. And that is also what is expected by onIceCandidate. https://github.com/shinyoshiaki/werift-webrtc/blob/18b4194c271410da132000e9e460424a6c8cc3f5/packages/webrtc/src/peerConnection.ts#L509-L513

[koush]

Another option is to queue the dropped candidates and flush them on setLocalDescription.

[koush]

I've fixed the underlying issue where setRemoteDescription is trigger candidating generation prior to createAnswer.

[koush]

I think this is finished now

[shinyoshiaki]

thanks!!