Implement mAP calculation for evaluation

[clementpoiret]

Complete the evaluation loop in hackathon/objectdetection.py's evaluate function by implementing mean Average Precision (mAP) calculation. This includes handling model predictions, postprocessing steps if needed, and comparing with ground truth.

[bernardev254]

With a strong background in machine learning evaluation metrics, I will complete the evaluation loop in hackathon/objectdetection.py by implementing the mean Average Precision (mAP) calculation. This involves processing model predictions, applying necessary postprocessing steps, and comparing results with ground truth to ensure accurate performance assessment.