jianjunz

This change allows application to get `PeerConnection` before publishing or subscribing. Then the application can create `RTCRtpTransceiver`s on the `PeerConnection` returned, and publish a stream with `RTCRtpTransceiver`s pre-configurated.

`PublicationSettings` is not tightly associated with a specific publication. It should be reusable.

SDK is still using `js` as file extension for modules. It's better to be switch to `mjs`.

Expose WebRTC objects, such as `RTCSender`, `RTCReceiver`, to developers. Once it is implemented, developers will be able to call WebRTC APIs on them.

Please add a readme for testing, including its prerequisites and steps to run tests. Thanks.

To avoid misusing of bot account @labwebrtctest (https://github.com/open-webrtc-toolkit/owt-client-android/pull/74), let's consider to develop a GitHub app to automotive CI process and send digests.

This issue was originally reported at https://software.intel.com/en-us/forums/intel-collaboration-suite-for-webrtc/topic/804984. > Environment: > - Ver: ICS 4.1.1 > - ICS-Conferece > - Do not use mixing. > > # log cat > 2019-02-11...

Compilation error reported on Linux for branch cloudgaming-83: ``` ../../third_party/webrtc/modules/congestion_controller/goog_cc/goog_cc_network_control.cc:79:7: error: use of undeclared identifier 'sscanf_s' sscanf_s(expr_str.c_str(), "Enabled-%u,%u,%u", start_bitrate_kbps, ^ ```