Update README to better explain local dev

[devinmatte]

Update the README to be better for describing what's needed for local development

We should break AWS Deployment info away from the README or to the bottom of the README

Make it as easy as possible for new people to onboard

[github-actions]

This issue has been automatically marked as stale because it has not had activity within 180 days.

[nathan-weinberg]

Unstale because this is important