perform create-table.js and etl.js for local, Node installs

[remrobem]

Description

allow execution of the create-table.js and etl.js scripts using argument "manual" to create and update local postgresql database with voter data. Readme updated with process to install postgresql and run the app locally.

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Checklist:

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.