Replace Autofill authenticators with those in lib-auth

[jonalmeida]

When https://github.com/mozilla-mobile/android-components/issues/12289 lands, we should use that component as dependency for feature-autofill so that we can reduce the duplication use the appropriate component.

We can remove the code in the mozilla.components.feature.autofill.authenticator package and with lib-auth replace that (maybe keeping the interface as well if it's appropriate).

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