Add Lts/Application module with Qt6 CMakeLists updates

- Copy Lts/Application from qt5-before (AarApp, OpApp, THP submodules)
- Update all CMakeLists.txt to use Qt6::Core, Qt6::Widgets, Qt6::Xml, Qt6::Network, Qt6::PrintSupport, Qt6::Svg, Qt6::WebEngineCore, Qt6::WebEngineWidgets
- No SIGNAL/SLOT, QRegExp, QDesktopWidget, or QTextCodec issues found in Application source code
- Module ready for Qt6 build validation

qt6-after/qt6-migrated-legatus/Lts/Application/THP/thpwidgets/thp_html_widget.h

@@ -0,0 +1,46 @@
+/**
+  * @RDE_HEADER@
+  * Handle HTML output for thp
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  */
+#pragma once
+#include <QWidget>
+#include <NGLLogger/INGLLogger.h>
+
+class QUrl;
+class QPrinter;
+namespace Ui
+{
+class HtmlWidget;
+}
+
+namespace THP
+{
+class HtmlWidget : public QWidget
+{
+  Q_OBJECT
+public:
+  explicit HtmlWidget(QWidget *parent = nullptr);
+  ~HtmlWidget();
+
+  void back();
+  void print(QPrinter *printer) const;
+  void setZoomFactor(double newZoomFactor);
+  QString title() const;
+  QUrl url() const;
+
+public Q_SLOTS:
+  bool showHTML(const QUrl &url);
+
+Q_SIGNALS:
+  void linkClicked(const QUrl &link);
+  void loadFinished(bool);
+  void urlChanged(const QUrl &url);
+  void titleChanged(const QString &title);
+protected:
+  Ui::HtmlWidget *ui;
+  NGL::INGLLogger &m_logger;
+};
+} // namespace THP