Better documentation and tutorials for slice and distribution files

[anilyil]

Description of feature

Once we merge #231, we will have some new capability to create slice outputs with more control over the planes used to slice the computational surface. For example, we can now do cylindrical slices; we slice radially out along an axis and compute the intersection between planes that rotate about this center axis and the surface mesh:

Thanks to @ArshSaja for providing the example slices for this image.

To avoid further delaying #231, I am creating this issue. This functionality should be documented better in tutorials as requested by @eirikurj.