Specify username while signing up through Cognito

[ethanstrominger]

Overview

As a user I want to make sure that anywhere username is used it is the same so that all my information can be consistent.

Background

Currently, Cognito is configured to only prompt for email. This has the potential to cause inconsistencies in other systems where username is used. This is particularly confusing because when you use allauth for a seamless experience, username is derived from email address. Both need to be consistent.

Action Items

• Modify Amazon Cognito user pool apps to include username as an attribute to collect.
• Modify documentation that specifies how you spin up Amazon Cognito app.