* add high-level docs about our components & remove stale detail info
* use current collection/folder naming in docs:
- let's rename js/components in a separate PR
- split paragraphs on to separate lines to improve future diffs
* rename storybook.md => components.md and update link/summary
* tweak component collection docs:
- base have more stringent requirements, since they can be used anywhere
- editor components are less strict and can assume editor context
* clarify js/base/components readme in line with main doc
* remove line about editor components being specialised to woo blocks