MP4: Support metadata tracks

### [REQUIRED] Support general metadata track in EXO mp4 extractor
Metadata track is increasing use for supporting rich features, e.g. IMU sensor data.
Currently EXO Mp4 extractor only supports google's camera motion media type.

### Proposed solution
Option 1:
Extract data from metadata track as general bytes data blob with timestamp;
maybe a subtype filter support subtype filter for select data track output;

### Link to test content
[GoPro gpmf](https://github.com/gopro/gpmf-parser/blob/master/samples/karma.mp4)