Update factory.py to work for batch of images

[cerebrai]

Description

The current implementation supports sending one image at a time. In some applications, sending a batch of images through the model and leveraging the GPU capabilities to speed up the processing would be useful. I have made slight modifications to the "forward" function in "factory.py" in the "models" folder. Now it accepts a single image or a list of images and do batch processing.

Tests

I tested it using the following code and it checks out
import cv2
import onepose

if __name__ == "__main__":
   
    model = onepose.create_model("ViTPose+_base_coco_wholebody")
    img1 = cv2.imread('/path/to/image1')
    img2 = cv2.imread('/path/to/image2')
    
    batch_img = [img1, img2]
    keypoints = model(img1)
    keypoints_batch = model(batch_img)

[developer0hye]

Hello @cerebrai,

Great suggestion, I will check it.

[developer0hye]

@cerebrai It is merged! Thanks for your contribution!