Write a document explaining how to use nitro

[lalexgap]

          Looks good.

This prompts me to think that we need some docs to explain to boost users:

• how to enable nitro
• what that means / enables for them.

Perhaps we should make an issue to cover this. I believe the boost maintainers are going to want to see that before considering our work.

Originally posted by @geoknee in #26 (review)