Dataset Conversion Scripts - COCO 2D bounding boxes

[adason]

Peer Review Information

This change resolves #171 which convert 2D bounding boxes into COCO formats.

Pull Request Check List

• [x] Added tests for changed code.
• [x] Updated documentation for changed code.

[adason]

@salehe-ee @Saurav-D I updated the PR with review changes. Can you take a look again? Thanks!