Clarify Active component APIs

[DHedgecock]

Summary

The Active component and its available APIs/use cases is a cornerstone of the library. Docs should be complete outlining all of the following:

• Component and subcomponent heiriarchy
• Using Active as a container for any active state management with FaCC pattern
• Componentry pattern of extending Active for all elements with active state
• Uncontrolled pattern usage
• Observed pattern usage
• Controlled pattern usage
• Combining uncontrolled usage with React keys to handle resetting uncontrolled instances

Additionally it would be ideal if these docs were in a shared Fragment that can be opened with a modal in any component that uses Active.