Add Credential Manager settings

Autofill is evolving into CredMan which means we need
to update the settings to have CredMan providers.

This CL adds CredMan equivalent classes to list the
Credential Manager providers and allow the user
to select a number of providers.

Test: Manual & atest SettingsUnitTests & make RunSettingsRoboTests -j
Bug: 253157366

Change-Id: Ice76187cfee91d844d211205b44b661acf2f6a44