Improve folder structure

[MartinaeyNL]

Let's try to clean up relative imports in the Storybook documentation.
Making a JS script for the build task, that copies over files from dist folders to a centralized /docs/generated folder would help.
And in general, moving the Storybook app out of its separate /apps folder would be nice,
as most of the documentation would be centralized in Storybook. I'm not expecting other apps to be added.