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/pinterest/index.ts

@@ -182,7 +182,9 @@ export interface PinterestPin {
   installVariables: ['APP_ID'],
   platforms: ['Android', 'iOS']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class Pinterest extends IonicNativePlugin {
   /**
    * Convenience constant for authentication scopes