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/file/index.ts

@@ -708,7 +708,9 @@ declare const window: Window;
   repo: 'https://github.com/apache/cordova-plugin-file',
   platforms: ['Android', 'Browser', 'iOS', 'macOS', 'Windows']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class File extends IonicNativePlugin {
   /**
    *  Read-only directory where the application is installed.