Storybook for extensions

[hifi-phil]

I appreciate this is still very early days and you might have thought of this already.

But when you release this first version will it be possible to run a storybook instance for an extension and pull in the css, design system and mocks so that an extension developer can have a component library and run interaction tests on their extension in isolation?

This will make building extensions much more robust and less likely to errors.