Improvements so audio media can be handled without having to deal with raw RTP packets (#1424)

* wip.

* wip.

* Fine tuned openai examples to use enhancements to audio endpoint.

* Fixed missig dependency.

* Adjustments to the audio and rtp interface for the openai webrtc connection.

* Merged master.

* Moved openai webrtc project to separate repo.

* Moved openai demos to new repo.

* Improvements so audio media can be handled without having to deal with raw RTP packets.

* Tightened up OPUS encoding logic in case channel count was ever somehow 0.

* Referenced new abstractions package.

* Updated example dependency versions and checked build.

Author: sipsorcery