Add setup instructions

[alldne]

Title

Add setup instructions

Description

This PR:

• closes #637
• closes #574
• adds setup instructions and dependencies to the README.md.
• adds a link to the postgres setup guide in the setup script.

Types of Changes

Put an x in the boxes that apply

• [ ] Feature (non-breaking change which adds functionality)
• [ ] Bug Fix (non-breaking change that fixes an issue)
• [ ] Breaking Change (feature/fix that causes existing features to not work as expected)
• [x] Documentation

Checklist

• [x] I have read the [contribute]contributing doc
• [ ] Classes, scripts, and environment variables follow existing naming convention
• [x] Lint and Unit tests pass locally
• [ ] New features on hardware have been tested on a local Raspberry Pi
• [ ] Mention new programs/binaries if any must be installed along with this change
• [ ] Mention new environment variables if any have been added to hardware/env file
• [x] Please make sure test coverage does not drop. If it does, please explain the reasons.
• [ ] Any new required python modules are added to the requirements.txt