Add accordion features to css properties list (#573)

* Add accordion features to css properties list

1. Add accordion features to css properties list in HTML
2. Add new function in JS to handle accordion click event
3. Update CSS types to support accordion feature
4. Update CSS for other things like font size to make the demo more compact

* Add accordion features to CSS properties controller

* Reduce font size and space to make it more compact

* Remove dist files

* Label font size / AC height change

* Fix the accordion styling issue

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Co-authored-by: William French <wfrench@google.com>

Author: teresarwqin