Major port Qt4 to Qt6

- Updated header inclusions from QtGui to QtWidgets for consistency and compatibility with Qt 5 and later.
- Replaced deprecated QApplication::desktop() with QApplication::primaryScreen() for obtaining screen DPI.
- Modified MyOutputHandler to use QMessageLogContext and QString for improved logging.
- Changed QMatrix to QTransform for image rotation in ImageCutout class.
- Updated various debug statements to use toLocal8Bit() instead of toAscii() for better string handling.
- Refactored several classes to use QElapsedTimer instead of QTime for performance measurement.
- Ensured all operator overloads in Section and Tag classes are marked as const for better const-correctness.

ClippingStation/Importer/imageoutputformatdialog.cpp

@@ -2,6 +2,7 @@
 
 #include "imageoutputformatdialog.h"
 #include "ui_imageoutputformatdialog.h"
+#include <QRegularExpression>
 
 ImageOutputFormatDialog::ImageOutputFormatDialog(QWidget *parent, QStringList list, bool keeppagenumber, int startpagenumber) :
     QDialog(parent),
@@ -19,7 +20,7 @@ ImageOutputFormatDialog::ImageOutputFormatDialog(QWidget *parent, QStringList li
         {
             QString name = list[i];
             //the newName value will be stripped down from all NON numeric character, and will output the name in the format dddd.jpg, where d is digit (0-9)
-            QString destinationName = QString("%1.jpg").arg(name.remove(QRegExp("[^\\d]")), 4, QChar('0'));
+            QString destinationName = QString("%1.jpg").arg(name.remove(QRegularExpression("[^\\d]")), 4, QChar('0'));
             outputFileNames << destinationName;
         }
     }