Update first-run README

[rahearn]

Story

As an engineer,
I would like to have a very clear process for the first deploy to cloud.gov,
So that I can get the app running right away

Solution

### Tasks
- [ ] update first-run readme and make really clear where it lives

Acceptance Criteria

• One criteria
• Another criteria

[kewlguy781]

Also may want to add to readme on how to run different enivorment, ex. dev, locally.