amplify-js: Ionic 4 / Angular 7 - aws amplify doesn't have Federated Sign in / Sign up

**Is your feature request related to a problem?

AWS Amplify for Ionic 4 doesn’t seem to have any way to complete federated logins using amazon, google, or facebook. I have seen documentation for React Native but none for Ionic 4, How would I enable federated sign in / sign up via social logins through the <amplify-authenticator> ?

Describe the solution you’d like I would like the ability to enable federated sign up / sign in / sign out while still being able to use the provided <amplify-authenticator> module / theme. I have seen React Native able to add a parameter to <amplify-authenticator> such as federated = {federated}, Why is this type of functionality not available for Ionic 4?

Describe alternatives you’ve considered Most preferably it would be great to have the Sign up / Sign in UI come with a toggle feature for social providers, and some documentation to go with it. It seems AWS Amplify is lacking for Ionic 4 and prioritizes React, it would be nice to see some of the features React has come to Ionic 4.

Additional context No way to enable federated sign in using the UI or other methods on Ionic 4 - AWS Amplify latest version.