I'm using the Authenticator component to authenticate my app. I'd like to be able to create my own Login page, or at the very least be able to insert a prop to the username/email field. I'd also like to be able to disable toast messages and a bunch of other customization. This was possible with the 1.x versions of amplify-ui, but I can't seem to be able to figure out how to do this with the 2.x version of Authenticator.