Add "Contextual Examples"

[engineerjoe440]

This project was born of my laziness... In college, I was interested in creating a couple Python modules to help me retain all of the formulas and functions I accumulated. Over those years, I used these functions in a variety of ways. Some of that still remains!

Some of those old exercises could be redrafted into valid examples to provide some contextual value to ElectricPy, and show more cohesive usage of the package.

Some of that old work lives here: https://github.com/engineerjoe440/ece_classes