[BB10] InAppBrowser Wrapper Plugin

Child browser functionality is natively supported by the BB10 webview. However if the inappbrowser plugin is installed via plugman, this overwrites the native functionality and causes failure of manual tests. This has been fixed in CB-4399.

To support CB-2655, CB-2412, CB-3420, etc, a wrapper plugin will be written which largely redirects to native functionality, but also adds the desired features.