Provide documentation for TOTP flow for JS

[abdallahshaban557]

Is your feature request related to a problem? Please describe. As an Amplify JS customer, I want to have a clear description and walkthrough of how to setup TOTP authentication using the Amplify JS library, so that I do not have to spend a lot of time in setting up my application.

Describe the solution you'd like Add a documentation page to the Authentication category documentation on docs.amplify.aws

Additional context There are steps mentioned here on how to make TOTP work in Amplify JS