feat(Auth): TOTP Clean up PR (#3048)

* feat(Auth): Adding TOTP support in Amplify Auth category

* feat(Auth): Adding TOTP related models to AWSCognitoPlugin

* feat(Auth): Adding TOTP service behaviour

* feat(Auth): Adding TOTP tasks and requests to AWSAuthCognitoPlugin

* feat(Auth): Adding TOTP state machine actions

* feat(Auth): Adding TOTP states, events, data models and resolvers

* feat(Auth): Add unit tests for TOTP

* feat(Auth): Adding TOTP implementation to Amplify

* feat(Auth): Adding TOTP integration tests