RandomRotate does not preserve range

[dermahax]

Hey,

when using RandomRotate with numpy arrays, the images are normalized. For most use cases it might be preferable to prevent the range of input imgs. Skikit.transform.rotate has the flag preserver_range (default False).

https://scikit-image.org/docs/stable/api/skimage.transform.html#skimage.transform.rotate

It could be a good idea to forward it to the user or set it to True in the va.RandomRotate class.

Cheers, Max.