feat(rules): natural-order rule

[moritzjacobs]

closes #13

As documented here: https://github.com/peerigon/scriptlint/wiki/natural-order

[jhnns]

I didn't really check the code, but from a user perspective I'd expect the config object to look more like this:

{
	"strict": true,
	"rules": {
		"order": "natural"
	}
}

As soon as there's the possibility to specify an invalid configuration, people will do it 😁

[jhnns]

Nice 👍 😁

[moritzjacobs]

Good point. This is so old, I can do my own review and maybe get this done :)