Add center_crop to ImageFeatureExtractionMixin
# What does this PR do?

This PR adds the center crop operation to `ImageFeatureExtractionMixin`. It works on PIL Images, NumPy arrays or torch tensors and behaves the same way as torchvision.transforms.CenterCrop: if the image is smaller than the desired size on a given dimension, it will be padded in that dimension.

Tests are added to check it works for all three types an give consistent results.