Expose Camera and Microphone

Feature description

Termux has a very complete collection of packages that can help to create a streaming server from the phone (eg. rtmpdump, icecast, nginx, etc), so I think it would be very useful to get the real-time data from those devices, instead of saving them to a file.

So to clarify the idea, I'm thinking of accesing the micro and camera as I would in a GNU/Linux system (through /dev/videoX or /dev/snd), but in this case would use the termux-api lib. So let's say I want to record from termux (with ffmpeg) my camera, it would be something like:

ffmpeg -i video=${termux-api Camera} -i ${termux-api Microphone} -o $OUTPUT

So ffmpeg is so versatile that $OUTPUT can be anything: a file, a streaming server, an URL, etc.

Reference implementation
Mobile WebCam - Though I couldn't manage to stream the camera through MJPEG (I believe because is outdated), it is supposed to do it.
Termux, SoX, PulseAudio - Here is an example of how to record the microphone input with pulseaudio, instead of termux-microphone-record

Start by reviewing the existing termux-api interfaces and the termux-microphone-record behavior, then compare them with the Mobile WebCam and Termux, SoX, PulseAudio references. The work is complete when camera and microphone data can be exposed in real time for tools such as ffmpeg, rather than only being saved to a file.