Major revision of WebRTC-QUIC

The QUIC API which was developed in the ORTC CG and is referenced in the ORTC API document has been broken out into a separate specification:
https://w3c.github.io/webrtc-quic/

The current specification, which was first published roughly a year ago, assumes that QUIC streams are bi-directional.  Since then, the QUIC transport document (https://tools.ietf.org/html/draft-ietf-quic-transport) has been updated to support uni-directional streams.

The lack of support for uni-directional streams in the QUIC API has been pointed out in a recent review by the W3C TAG and in addition it has become clear that support for uni-directional streams is required for WHATWG Streams support.

Seth Hampson has put together a PR for a major refactoring to add support for uni-directional streams as well as to address the following Issues:


  *   50<https://github.com/w3c/webrtc-quic/issues/50> - restricting createStream to state = connected
  *   54<https://github.com/w3c/webrtc-quic/issues/54> - new/open/opening for a stream
  *   55<https://github.com/w3c/webrtc-quic/issues/55> - remote stream triggering with data sent
  *   61<https://github.com/w3c/webrtc-quic/issues/61> - Reset/STOP_SENDING
  *   64<https://github.com/w3c/webrtc-quic/issues/64> - readable/writable access
  *   65<https://github.com/w3c/webrtc-quic/issues/65> - Taking out RTCQuicStreamState
  *   69 - Unidirectional stream support

The PR is available for inspection here:
https://github.com/w3c/webrtc-quic/pull/70

While a number of issues have come up in the review of the PR (including whether the API should be modified further to incorporate support for WHATWG streams), it also appears to represent a more solid base for further discussion than today's specification, which lags badly behind the functionality in the QUIC transport document.

In particular, at TPAC on Tuesday October 23, we will be having a discussion of the further changes to the QUIC API needed to support WHAT WG streams.  Slides relating to that discussion will be available here:
https://docs.google.com/presentation/d/1WOihY0SMJbWvfbc-41GA78F4yzPSwmyDOJ8GbRoU7dw/

Since that discussion assumes support for uni-directional streams as a pre-requisite, it has been suggested that we merge Seth's PR so as to help participants understand better how uni-directional stream support works and would need to be modified for WHATWG stream support.

Any objections to merging Seth's PR?