Add option to use BBox tracking with SORT algorithm:

[ManuelPalermo]

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Hi, tried improving detection consistency across frames using BBox tracking with the SORT algorithm (https://arxiv.org/pdf/1602.00763.pdf). The implementation was completely ported from the original author (https://github.com/abewley/sort)

[mdraw]

Thanks for your work @ManuelPalermo, that sounds like a great feature! I'm not sure if everything works as it should with the given default configuration though. I've tested your implementation on some rather challenging video clips and found that with the default settings (--track-config '{}') there were actually more missing face detections. For example using --track-config '{"max_age": 100, "min_hits": 0, "iou_threshold": 0.01}' instead, the results were similar to not using the tracking feature at all. Can you recommend a good default setting with which the results are improved? In addition, can you share a video clip where you see an improvement by using the new tracking feature so I can test it?