Support for instance proposals (bounding boxes)

[Hendrik-code]

Describe the solution you'd like
Add a datatype called boundingBoxPair, which will be converted to either semanticPair or unmatchedinstance pair internally after initialization.

Additionally, we need metrics like AP, mAP, (https://github.com/rafaelpadilla/review_object_detection_metrics/blob/main/src/evaluators/coco_evaluator.py#L290)
sortedAP (https://arxiv.org/pdf/2309.04887.pdf)

Also AJI and AJI+ (https://github.com/vqdang/hover_net/blob/master/metrics/README.md)

[neuronflow]

hmm then one might also consider RoDeO https://github.com/eoezkaya/RoDeO