Lesson to be updated: React Hooks

Summary of changes needed:

Current lesson presents useState() and useEffect() in the context of how to use them instead of the way students had been doing it using class components.
Need to update this lesson so that it is not relying on the context of class components.
This lesson should introduce students to:
- the useEffect() hook
- how to make network requests in their React applications
- conditional rendering
Create repo (or branch) and activity for students to be able to implement useEffect, fetch and conditional rendering. The current repo/activity linked in this lesson is being used in the class components lesson. Students will be refactoring the class components into functional/hooks in that lesson

This revised lesson will somewhat replace the info in the deprecated Advanced Data Management (Lifecycle Methods) lesson and the original React Hooks lesson (Intermediate React Hooks).