Add #[RestrictTraitTo]

[DaveLiddament]

This limits the use of a Trait to only be used by a specified class of a child of that class.

E.g. this trait is limited to classes that are or extend Controller

#[RestrictTraitTo(Controller::class)]
trait ControllerHelpers {}

This would be allowed:

class LoginController extends Controller {
    use ControllerHelpers;
}

But this would NOT be allowed:

class Repository {
    use ControllerHelpers;
}

[DaveLiddament]

Actioned #33