[Review]: Rotation fixes for non-centered maps, submaps, and skimage/scipy consistency

An AIA submap is working but my HMI submap test is not working. More details to follow.

Assistance appreciated.
Another suggestion: point out that the default order of 3 corresponds to bicubic interpolation for scikit-image

Also, the docstring note about the two different options for transform seems like it should be in the docstring of `sunpy.image.transform.affine_transform()`, and referred to from here