Uncertainty budget calculations

This merge request implements the O3 version of the uncertainty budget in the pyDARM framework. Much of the code is recreated from the O3 implementation RRNom.py but does it in a much more robust way.

This is still in a draft form because this has not been tested, there are no unit tests, and there are still missing pieces. The code will likely need to be improved in subsequent commits to this feature branch, but I wanted to advertise that this is underway.

Addresses #8 (closed)