Add ESLint to lint all our JS/JSON

[humphd]

We should really have a proper automated linting step using ESLint. You can see good docs on how to do this at https://eslint.org/docs/user-guide/getting-started, and look at how lots of other projects do their linting by reading their .eslintrc file(s).

Until we get automated tests written, this can serve as our npm test step, and let us start automating CI in other bugs.

[kartik-budhiraja]

We can use Airbnb Javascript style guide as starting base and extend it. The eslint config is available through npm package eslint-config-airbnb-base.

[UltimaBGD]

In the event Airbnb style is something we are interested in, I will quickly put up a pull request with it setup for people to test with.

[UltimaBGD]

The pull request has been merged, shall we close this issue or keep it up for further discussion?

[humphd]

Close. Also, we should make sure that people use the "Fixes " style in their PRs so GitHub will auto-close issues fixed by PRs.

Thanks for working on this!