Configure navigator for authentication

Bug

What: App currently allows the user to use the back button to go back to login screen
Why: The routing has not been configured and it is confusing and the feature should not be there. Currently, the AddNavigator holds the login type
B User Case: As a user, I don't want to accidentally log myself out

Testing

Given I have logged in as a user
I should not be able to see the back button once the app has navigated to the Home Screen
- The Home Screen should be the Add Screen

Edited Dec 10, 2019 by Kristina Hoeppner

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