Add COCO image label provider

[agibsonccc]

What changes were proposed in this pull request?

Adds COCO Image Label Provider for training on object recognition datasets

How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)

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[archenroot]

hi, what about this PR? any plans?

[agibsonccc]

This had some edge cases. Unfortunately paid work came up and I had to prioritize that. More immediate QA is also taking precedent.