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/web-intent/index.ts

@@ -76,7 +76,9 @@ export interface IntentOptions {
     'https://github.com/darryncampbell/darryncampbell-cordova-plugin-intent',
   platforms: ['Android']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class WebIntent extends IonicNativePlugin {
   /**
    * Convenience constant for actions