Android: Some code cosmetics

The naming scheme of the internal object was changed
to the usual pimpl pattern.

Also setup device update connection in the device constructory

Change-Id: I5cbb7a9d870a7d1f0e91e54f2ad6dfb95ea63e37
Reviewed-by: Vikas Pachdha <vikas.pachdha@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/android/androidconfigurations.cpp

@@ -1145,6 +1145,8 @@ AndroidConfigurations::AndroidConfigurations()
 
     connect(SessionManager::instance(), &SessionManager::projectRemoved,
             this, &AndroidConfigurations::clearDefaultDevices);
+    connect(DeviceManager::instance(), &DeviceManager::devicesLoaded,
+            this, &AndroidConfigurations::updateAndroidDevice);
 
     m_force32bit = is32BitUserSpace();