New `setup` module for dev|test|prod settings

This branch provides with a back-end refactor moving some stuff from the app's entry-point `index.js` to `boot/index.js`. Also leaves `config/` free of any script, and now it only contains environment settings for `devevlopment`, `testing` and `production`. All previous `express-app` config settings have been moved to the new `setup` module under `lib`.

This is a separation of concerns that was causing problems on new developers into approaching a complete understanding of the application flow.