[packagechooser] Add selection modes

- Introduce different selection modes (most don't work yet)
 - Use model data in the main widget

src/modules/packagechooser/PackageModel.cpp

@@ -83,10 +83,18 @@ PackageListModel::data( const QModelIndex& index, int role ) const
         return QVariant();
     }
 
-    if ( role == Qt::DisplayRole )
+    if ( role == Qt::DisplayRole /* Also PackageNameRole */ )
     {
         return m_packages[ row ].name;
     }
+    else if ( role == DescriptionRole )
+    {
+        return m_packages[ row ].description;
+    }
+    else if ( role == ScreenshotRole )
+    {
+        return m_packages[ row ].screenshot;
+    }
 
     return QVariant();
 }