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/adjust/index.ts

@@ -295,7 +295,9 @@ export enum AdjustLogLevel {
   repo: 'https://github.com/adjust/cordova_sdk',
   platforms: ['Android', 'iOS']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class Adjust extends IonicNativePlugin {
   /**
    * This method initializes Adjust SDK