Need to add labels to Auto Annotation's Run Model Script

[benhoff]

Currently Auto Annotation's run_model.py has a way to visualize the results, but it doesn't have any way to visualize labels. This has lead to off-by-1 errors in development.

Ref: #912
Ref: #890 (comment)

Need to add the ability to visualize labels to ensure the mapping.json remains accurate.

This should be relatively easy. See below for a reference implementation:

https://github.com/opencv/open_model_zoo/blob/e372d4173e50741a6828cda415d55c37320f89cd/demos/python_demos/object_detection_demo_yolov3_async/object_detection_demo_yolov3_async.py#L318

Note that when using the --serialize command, the text label is actually overwritten (for reasons that are explained in the note starting at this link) in the following line:

https://github.com/opencv/cvat/blob/32027ce884c0584015874c4ae99ba7f53ffb46c0/utils/auto_annotation/run_model.py#L126

The above overriden data would need to be preserved by some programmatic means to preserve the plain english descriptions. A simple dictionary copy before re-writing at line 126 would likely suffice.