[libcalamaresui] Expose currentIndex also as model data

src/libcalamaresui/ViewManager.cpp

@@ -559,6 +559,8 @@ ViewManager::data( const QModelIndex& index, int role ) const
         {
             return QVariant();
         }
+    case ProgressTreeItemCurrentIndex:
+        return m_currentStep;
     case ProgressTreeItemCurrentRole:
         return currentStep() == step;
     case ProgressTreeItemCompletedRole:

src/libcalamaresui/ViewManager.h

@@ -154,7 +154,8 @@ public:
     enum Role
     {
         ProgressTreeItemCurrentRole = Qt::UserRole + 11,  ///< Is this the *current* step?
-        ProgressTreeItemCompletedRole = Qt::UserRole + 12  ///< Are we past this one?
+        ProgressTreeItemCompletedRole = Qt::UserRole + 12,  ///< Are we past this one?
+        ProgressTreeItemCurrentIndex = Qt::UserRole + 13  ///< Index (row) of the current step
     };
 
     QVariant data( const QModelIndex& index, int role = Qt::DisplayRole ) const override;