Add patching to BRACS benchmark

[nkaenzig]

Contributes to #774

Motivation

BRACS (the ROI subset) contains a wide range of different image sizes (some are smaller than 224x224, while the largest image is 17611x9842 (those huge images are outliers though). Many images are clearly bigger than 224, therefore just resizing all the images to 224x224 results in information loss and uncommon mpp values the FMs haven't been trained on.

What this PR does

• Applies patching to the BRACS dataset
• Update feature to patching logic to include patches that partially exceed the original image (without that, for instance if your image is 400x400, you would only extract one 224x224 patch while discarding the rest of the pixel information). On the other hand, with include_partial_patches=True we extract 2x2 patches where two of them need to be padded.