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/firebase-analytics/index.ts

@@ -33,7 +33,9 @@ import { Cordova, IonicNativePlugin, Plugin } from '@ionic-native/core';
   repo: 'https://github.com/chemerisuk/cordova-plugin-firebase-analytics',
   platforms: ['Android', 'iOS']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class FirebaseAnalytics extends IonicNativePlugin {
   /**
    * Logs an app event.