Use case based tutorial

**Is your feature request related to a problem? Please describe.**
As a new developer to Amplify, I'd like to learn how to build an app by an experiential learning so that I can gradually make the app my own app.

**Describe the solution you'd like**
Having use case driven tutorial with example code that can be pulled via `git clone` and Video guide or FAQ to answer to pitfalls developers may face. Let me list in details in the below:
1. Use case needs to be put first as the new developer craft tutorial app and their own idea at the same time.
2. Git clone based tutorial helps new developers to kick off their tutorial
3. Video guide to answer to questions that the new developers may have.

As an example, GraphQL has the great tutorial docs that covers the above points.
https://odyssey.apollographql.com/

React also has the great tutorial with trouble shooting links that developers may face during tutorial
https://reactjs.org/tutorial/tutorial.html

**Describe alternatives you've considered**
The solution can be implemented one by one and totally fine to make subtasks.

**Additional context**
Some front-end developers who use AWS started learning Amplify to build their app on AWS quickly and I heard the above pain points.