A withStoryStyle configuration item is needed

[Mr-VincentW]

Thank you for this brilliant work, it helps a lot!

I wonder if I can use arbitrary templates for files generating? For example, When using storybook, quite often I need a TemplateName.stories.css file for styling the story. So, it'll be good to have a wihtStoryStyle configuration item for adding this file template. Or maybe consider removing all the with*** configuration items and just generating all files from templates under the customTemplates directory?

Thank you.