Auth Adapters refactoring (#3177)

* 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

src/Adapters/AdapterLoader.js

@@ -17,6 +17,7 @@ export function loadAdapter(adapter, defaultAdapter, options) {
       }
     }
   } else if (typeof adapter === "string") {
+    /* eslint-disable */
     adapter = require(adapter);
     // If it's define as a module, get the default
     if (adapter.default) {