Add getting started example

[kylebuckingham]

We need a simple hello world-like example. It would also be nice to pull benchmarks from the paper out on the main page

[Aristarhys]

As option it can be ipynb? They are displayable in github directly (with some limitations)

https://docs.github.com/en/github/managing-files-in-a-repository/working-with-jupyter-notebook-files-on-github

Cell 0

 import sys
 !{sys.executable} -m pip install luminaire
 !{sys.executable} -m pip <other deps>

Cell 1

from luminaire.exploration.data_exploration import DataExploration
...