Linting and build failure with actions

[swiftlee]

Add an ESLint configuration (we can come up with some general rules for our code if needed).

Integrate this with GitHub actions such that feature branches will fail actions on linting errors.

Master branch will fail to deploy and build on linting errors.

[up16]

I can work on this one. I have a question, can we add pre-commit hook to check for linting errors and auto fix errors (where possible) before making a commit.