Update to the Button component stories to add knobs (#581)
* Fix for https://github.com/adobe/react-spectrum/issues/561. Updated the Button stories to use knobs and organized the examples by logical types
* fix lint errors
* Incorporate PR feedback.
* Updated background color to static green 700, which is a valid bacvkground color.
* PR comment fix, remove console.log statement.
* Integrated PR feedback. Added back the original stories because the RS team depends on them for testing. Created a new folder - Interactive - for the new stories that showcase the knobs
* Separated the interactive stories into their own file.