Bug 1032071 - [Settings] Remove BT panel and embed it from BT app

nit: We usually place AMD modules together. I would suggest to modify these lines to:
```
var NavigatorBluetooth = require('modules/navigator/mozBluetooth');
var BluetoothHelperModule = require('shared/bluetooth_helper');
var Observable = require('modules/mvvm/observable');

var settings = window.navigator.mozSettings;
```