Make a policy for ruff rule inclusion

[nathanjmcdougall]

Motivation
Some ruff rules are more controversial than others. With opinionated defaults, users might stumble across rules which don't match their usual workflow. There might be a few responses:

• Objection/Paternalism - not change the default usethis config and ask the user to change their way of working. This is sometimes justified, one of the objectives with usethis is to make it difficult to avoid best practice.
• Agreement - i.e. we'll disable the rule: it's either a questionable or at least controversial rule - erring on the side of caution seems wise.
• Defer - wait for more feedback to accumulate; is this just a one-person issue or is the problematic rule commonly an issue?
• Multiple behaviours - somehow codify the different workflows with their own usethis interface. This is more work but presumably gives the best UX. There's still a default behaviour though, so controversy isn't necessarily avoided.

But how do we assess a rule to decide on its inclusion? How is this decision actually made? Yes, it will always be opinionated to some degree, but some thought needs to go into the actual policy so it can be documented.

Summary of desired enhancement
Consider a policy for when a rule rule should be included or not.