A refactored version of `pybx` built using `nbdev`.
Added:
- documentation page: [docs](https://thatgeeman.github.io/pybx/), README.md, example walkthrough file
- GH workflow tests
Breaking changes:
- Need `area()` and `valid()` are now properties of BaseBx, so `.area` and `.valid` would suffice
- `utils` methods refactored to `utils` and `ops`