Make trivia/whitespace (Prettier) rules opt-out

[JoshuaKGoldberg]

🚀 Feature Request

Following #2 and #301, I really want to harp on the opinion that a linter (ESLint) should be separate from the formatter (Prettier). Having folks need to opt-in with a CLI flag in order to get that behavior will further that cause.

Existing Behavior

Right now, all existing TSLint rules will be output to the ESLint output - even Prettier-related ones such as whitespace.

Change Proposal

If a rule is disabled by tslint-config-prettier, it should only be output if a new CLI flag is provided.

[KingDarBoja]

Not an expert on the topic, but maybe InquirerJS would help to accomplish that.

[JoshuaKGoldberg]

Hmm, I've thought about this a bit, and I think it'd be better not to surprise users with a change in their configuration. #412's first commit e92888c makes this behavior default with an --ugly opt-out. We (linter aficionados) might prefer that but there's a case for users who can't or don't use Prettier getting surprised and irritated by it.

Instead, let's switch to a --prettier CLI option as a utility.