refactor(TwoFactorAuthentication): Remove references to old Duo SDK version 2 code and replace them with the Duo SDK version 4 supported library DuoUniversal code.
Increased unit test coverage in the Two Factor Authentication code space. We opted to use DI instead of Inheritance for the Duo and OrganizaitonDuo two factor tokens to increase testability, since creating a testing mock of the Duo.Client was non-trivial.
Reviewed-by: @JaredSnider-Bitwarden
* inital changes
* add provider GatewayType migrations
* db provider migrations
* removed duo migrations added v2 metadata to duo response
* removed helper scripts
* remove signature from org duo
* added backward compatibility for Duo v2
* added tests for duo request + response models
* refactors to TwoFactorController
* updated test methods to be compartmentalized by usage
* fix organization add duo
* Assert.Empty() fix for validator
