Implement function to decompose affine transforms

### Description

A generalized affine transform can be represented as a composition of a `projection*translation*rotation*shearing*scaling` matrices, there are many applications where a user might be interested in extracting a specific component for use.

A derivation of one possible implementation is available here
https://caff.de/posts/4X4-matrix-decomposition/decomposition.pdf

I am currently hacking together a version using SimpleITK/numpy, I am not familiar enough with the internals of ITK to directly implement this (yet...)

### Expected behavior

A function that operates on affine transforms and returns decomposed matrices.