Add Py03 bindings

[stevenparkerco3]

What can be improved or is missing?

Adding a simple Python3 binding will allow this excellent library to be used within Python. To begin with, being able to read image metadata, or possibly image pixels out of an EXR and possibly extending that to writing exrs as well in the future.

Implementation Approach

Could use the standard Py03/maturin build process to create simple python bindings.

[johannesvollmer]

Unfortunately, I currently don't have time for large tasks on this project. As always, any contributions are welcome and I will definitely be able to take some time to help plan and review any contributions. :)