Add CLI option to disable rules

[rgoldberg]

New Issue Checklist

• I've Updated SwiftLint to the latest version.
• I've searched for existing GitHub issues.

Feature or Enhancement Proposal

Please add a CLI option to disable rules, presumably named --disable-rule <rule-name>, which can be provided 0 to many times.

This is useful for ad hoc disabling of rules without needing to modify a config file, which can be a pain & can lead to accidental rule disabling being committed to the repo.

Thanks.