Add `sv.RoundBoundingBoxAnnotator` which annotates bounding box with round edges

[xaristeidou]

Description

This annotator will draw a bounding box which has round edges based on roundness attribute which accepts float values < roundness <= 1.0.

By default, roundness attribute percentage value is calculated based on the smaller size dimension (width or height). For example if height < width, and roundness is 1.0, the height dimension will be rounded completely.

This PR implements issue #693 .

Execution time of annotation process (tested on Ryzen 7 5800H):

• Exec time for 35 objects: 0.0018765926361083984
• Mean exec time for each object: 5.361693246023995e-05

No new dependencies required for this change.

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

I tested annotation results on walking people demo video. I used YOLOv8 to get the detection results. Screenshot of demo, using roundness = 0.5, is presented below:

Any specific deployment considerations

• Add new annotator class in Documentation.
• Add image example link reference in class Description in annotators/core.py

Docs

Docs not updated. Need to be updated with new annotator.