Move registration of App plugin from config.xml -> code

Less fragile this way.

framework/res/xml/config.xml

@@ -43,8 +43,4 @@
       <preference name="InAppBrowserStorageEnabled" value="true" />
       <preference name="disallowOverscroll" value="true" />
     -->
-    <!-- This is required for native Android hooks -->
-    <feature name="App">
-        <param name="android-package" value="org.apache.cordova.App" />
-    </feature>
 </widget>