Honda -- when you build an XDK app you are building a Cordova (aka PhoneGap app). The app runs in a "native webview." If you choose Crosswalk it simply means the native webview is replaced with the Crosswalk webview. In both cases your app is running inside a webview, it is not running in a browser.
The cordova-plugin-whitelist you are referring to is automatically added to your project when it is build. The rules you define in the whitelist section of the Build Settings (on the Project tab) create rules that are used by that plugin. You should not be adding that plugin to your application, it will be automatically added. That plugin works in the background to determine which external resources your app is allowed to access, it does not turn your web site into an app, it simply defines the rules associated with external access from within the webview.
If you want to turn your website into an app I recommend you search for examples by searching for something like "Cordova app from my website" or something like that.
If all you want to do is open a page of your website, from within the webview, I recommend you use the inAppBrowser plugin. See that plugin's documentation for examples on how to use it.
