refactor: optimize plugins for angular treeshaking

BREAKING CHANGE: You can remove the plugin import from the app.module.ts because of the changed Inject decorator

src/@ionic-native/plugins/device/index.ts

@@ -26,7 +26,9 @@ declare const window: any;
   repo: 'https://github.com/apache/cordova-plugin-device',
   platforms: ['Android', 'Browser', 'iOS', 'macOS', 'Windows']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class Device extends IonicNativePlugin {
 
   /** Get the version of Cordova running on the device. */