Implement `cv::integral`

[edgarriba]

🚀 Feature

Implement the pytorch version of cv::integral

https://docs.opencv.org/4.6.0/d7/d1b/group__imgproc__misc.html#ga97b87bec26908237e8ba0f6e96d23e28

Some reference:

• https://github.com/scikit-image/scikit-image/blob/main/skimage/transform/integral.py
• https://discuss.pytorch.org/t/is-there-an-elegant-way-to-calculate-integral-image-using-pytorch-api/22669/5

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[AnimeshMaheshwari22]

Hello. Some questions regarding this.

1. Is the expected output a tensor with all values as sum of left values in its row and top values in its column?
2. Which module does it go to?

[edgarriba]

well check the scikit implementation -- it can be easily implemented with cumsum /cc @ducha-aiki

def integral_image(image: Tensor) -> Tensor:
    S: Tensor = image
    S = S.cumsum(dim=-1)  # along columns
    S = S.cumsum(dim=-2)  # along rows
    return S