Add builtin rules for whitespaced code

[nervetattoo]

I think it makes sense to ship builtin rules for both tab and whitespace indentation.
Too many projects will be using different rules here so it doesn't make sense that every project needs to write custom code just to enforce their standard.

I suggest we rename the HasTabsAsIndentation to HasCorrectIndentation and passes the actual rule as a configuration:

{
    "variables": {
        "HasCorrectIndentation": {
            "character": "\t",
            "num": 1
        }
    }
}

I'll create a PR if theres no disagreement to this.

[jails]

Yeah pretty agree for merging HasCorrectTabIndention and HasTabsAsIndentation to a configurable HasCorrectIndentation rule.

[nateabele]

👍