ImageViewer: Remove class ImageViewerActionHandler.

Create the actions in ImageViewerPlugin and
use lambdas instead of a QSignalMapper.

Change-Id: Ic74622ca5e9daf6f0d367d00b709d732153dc62e
Reviewed-by: Alessandro Portale <alessandro.portale@theqtcompany.com>

src/plugins/imageviewer/imageviewerfactory.cpp

@@ -57,10 +57,5 @@ Core::IEditor *ImageViewerFactory::createEditor()
     return new ImageViewer();
 }
 
-void ImageViewerFactory::extensionsInitialized()
-{
-    m_actionHandler.createActions();
-}
-
 } // namespace Internal
 } // namespace ImageViewer