Bug 1069915 - [PP] Land Privacy panel app in /dev_apps

Because ppApp need this value to be set before opening, the better timing to launch it would be
```javascript
var self = this;
lock.onsuccess = function() {
  self._ppApp.launch()
};
```

You can check https://developer.mozilla.org/en-US/docs/Web/API/Settings_API#Changing_settings for more information