Document how to build this project

I started this project _ages_ ago, but never documented how to configure it. Every now and then, I dust this project off and have to re-read my own CMake logic just to understand what I did. Ideally, this should be better documented in the `README.md`. Maybe even properly configured easily with some bash scripts.

There is a `how-to-build` file, but it's sorely outdated. This should be improved.

## Acceptance Criteria

* Setting up and building this project is properly documented / easy to follow

### Stretch Goal

* An easy-to-use bash script is added for configuring/building quickly