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/battery-status/index.ts

@@ -47,7 +47,9 @@ export interface BatteryStatusResponse {
   repo: 'https://github.com/apache/cordova-plugin-battery-status',
   platforms: ['iOS', 'Android', 'Windows', 'Browser']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class BatteryStatus extends IonicNativePlugin {
   /**
    * Watch the change in battery level