LPS-48387

cc/ @epgarcia
Why not create a generic `developer.mode.enabled` property that when set to false will override all developer-related features?

We could start by simply overriding `theme.css.fast.load`, and add some others later on such as `theme.images.fast.load`, `minifier.enabled`, `javascript.fast.load`, `freemarker.engine.modification.check.interval` and so on...