text: Title: Support for loading geotiff files as a part of the ImageFolder
  Body: ### Feature request
  
  Request for adding rasterio support to load geotiff as a part of ImageFolder, instead of using PIL
  
  ### Motivation
  
  As of now, there are many datasets in HuggingFace Hub which are predominantly focussed towards RemoteSensing or are from RemoteSensing. The current ImageFolder (if I have understood correctly) uses PIL. This is not really optimized because mostly these datasets have images with many channels and additional metadata. Using PIL makes one loose it unless we provide a custom script. Hence, maybe an API could be added to have this in common?
  
  ### Your contribution
  
  If the issue is accepted - i can contribute the code, because I would like to have it automated and generalised.