Supercharge `klint` configuration with `logLevel` option — or similar behavior

I'm using `klint` for `kotlinGradle`. I couldn't find how to set the log level in order to figure it out what's causing some changes when auto-formatting.

I guess _augmenting_ `BaseKotlinExtension.KtlintConfig` with `logLevel` should do it?

Bonus points for an `enum` with the log levels — and supporting a string value as well for those who don't want to go back and forth with the `import`s 😅