Setup ESLINT and Prettier

**Current Behavior**
We don't have a common code style that is enforced across the codebase.

**Expected Behavior**
There is a linter that detects errors early and is enforced on builds.
There is a code formatter that forces everyone to agree on a code style and is enforced on builds.
IF either of those fail, then the build should fail.

Setup eslint for linting, and prettier for formatting.
https://dev.to/thomaslombart/how-to-setup-eslint-and-prettier-for-your-react-apps-1n42
https://dev.to/knowankit/setup-eslint-and-prettier-in-react-app-357b

Make builds fail when either of those tools fail.