Develop image class for handeling of the WSI and generated analysis layers

[jonaspk98]

So far OpenSlide was used to read images. However, it might be useful to store some of the generated data like ROI masks or secondary images like the deconvoluted channels in a pyramidized manner. The functionality needed would are:

• read
• write
• generating the pyramidal levels
• read_regions

• tifffile library might be useful for that