Update README

[jps327]

• [x] Make sure description of Scout is up-to-date
• [x] Update Roadmap section to say it'll be posted soon (next sprint)
• [x] Update Development section to make it easier to read and follow.
• [x] Add description that postgres installation through Homewbrew is recommended. If they have a postgres password they will need to edit the ormconfig.json.
• [x] Allow postgres pw to be overridable through env var, and update Development section to explain this
• [x] Add explanation of the Env Vars that need to be configured
• [x] Add link to GitHub discussion or email link they can use
• [ ] Add video or animation showing how the tool works [NOT DOING THIS RIGHT NOW]
• [x] Update screenshot

[jps327]

Blocked on CI, prod build, and contributing.md update

[jps327]

Update on blockers: Blocked on contributing.md and postgres pw env var override