Media streaming support in Soletta

[lblim]

Task Description

So far only sensor data collection is being supported in Soletta, media streaming is not supported yet. Media streaming is needed for use cases like simple digital surveillance use case that using IP camera to stream the video and audio, record video and audio, image snapshot, etc.

The request does not mean to replicate gstreamer, it can be a node or generic API for media subsystem whether the backend is GStreamer or some other library or even have multiple choices that can let user to choose. Just like the wrapper of MQTT implementation in Soletta.

Some notes from discussion with Gustavo, his suggestion:

• a player API that receives an URL and some output? Then some API to list the outputs? (ie: audio devices, video devices...).
• If the URL is a local video device and the output is an RTP, then it would stream video. If the output is a file, it would save.
• define what is the output device, how to list and create one.

[lblim]

@laykuanloon @fulong82 @elvinongbl