rm many unused fcts, detected with xunused

detected using xunused (described in Developer's corner).

GUI/Model/Mask/MaskContainerModel.cpp

@@ -60,15 +60,6 @@ void MaskContainerModel::insertMask(int row, MaskItem* item)
     QAbstractListModel::endInsertRows();
 }
 
-void MaskContainerModel::maskToModel(MaskItem* item)
-{
-    qsizetype row = m_maskContItem->size() - 1;
-    QAbstractListModel::beginInsertRows(m_maskContItem->rootIndex, row, row);
-    m_maskContItem->addMaskItem(item);
-    QAbstractListModel::endInsertRows();
-}
-
-
 //! Move mask to a given row
 void MaskContainerModel::moveMask(int from_row, int to_row)
 {
@@ -91,15 +82,6 @@ void MaskContainerModel::removeMask(MaskItem* item)
     removeMaskAt(row);
 }
 
-RegionOfInterestItem* MaskContainerModel::regionOfInterestItem() const
-{
-    for (MaskItem* maskItem : m_maskContItem->maskItems())
-        if (auto* reg = dynamic_cast<RegionOfInterestItem*>(maskItem))
-            return reg;
-
-    return nullptr;
-}
-
 QModelIndex MaskContainerModel::indexOfItem(const MaskRoot* item) const
 {
     if (const auto* ii = dynamic_cast<const MaskItem*>(item)) {