* Integrate auth adapter for Facebook accountkit login
* Also verify Facebook app id associated with account kit login
* Add appsecret_proof as extra graph request parameter
* Specific error message for Account kit and more test coverage
* One more test to cover when AppIds for Facebook account kit not configured properly
* Moves all authentication providers to Adapter/Auth
* refactors specs
* Deprecates oauth option in favor of auth option
- Deprecates facebookAppIds option (in favor of auth.facebook.appIds)
- Adds warnings about the deprecated options
* nits