Contributor doc

[zachharris1]

Contributor docs for making approved taps

[luandy64]

If people are working on this, I highly recommend grip for previewing the markdown.

[luandy64]

I want to track some resources we might pull from.

These are the first few results from "how to write a contributing.md":

• https://mozillascience.github.io/working-open-workshop/contributing/
• https://gist.github.com/PurpleBooth/b24679402957c63ec426#contributing
• https://gist.github.com/briandk/3d2e8b3ec8daf5a27a62
• https://github.com/atom/atom/blob/master/CONTRIBUTING.md
• https://gitlab.com/gitlab-org/gitlab-recipes/-/blob/master/CONTRIBUTING.md
• https://github.blog/2012-09-17-contributing-guidelines/