Feature: Add initial YOLO integration for face detection

[sohamgupta779-art]

Summary

This PR introduces initial support for YOLO-based face detection in the face_recognition library.

Changes Made

• Imported YOLO library into api.py.
• Added a YOLO-based detection option alongside existing HOG/CNN detectors.

Motivation

The current library only supports HOG and CNN detectors. YOLO is widely used for real-time object detection and offers an alternative approach for face recognition workflows.

Notes

• This is an initial integration — testing and example scripts are not yet included.
• Future work could extend this by adding a dedicated test_yolo_face.py and benchmarking YOLO vs. CNN/HOG.
• Maintains backward compatibility (no changes to existing HOG/CNN paths).

Impact

• Enables developers to experiment with YOLO face detection inside the face_recognition framework.
• Lays the groundwork for performance improvements in real-time applications.