Qt6 Migration: Complete migration with DDS/RTI support and build validation

Major Changes:
- Merged latest Qt5 devel content from dlbo (292 files changed, 7 new dirs)
- Consolidated forward-declarations and include folders
- Removed unneeded modules per Niklas' repo check list

Build System Fixes:
- Fixed CMake VERSION_GREATER syntax in ParticipantManagement/CMakeLists.txt
- Added VLC packages (libvlc-dev, vlc-plugin-base) to docker_build.sh
- Added PostgreSQL dev packages (libpq-dev, postgresql-server-dev-all) to Dockerfile
- Fixed locale warnings (ANSI_X3.4-1968 → C.UTF-8)
- Fixed ArcGIS SDK path warnings when BUILD_ARCGIS=OFF

Code Generation Fixes:
- Fixed IDL enum collisions (PortType→CorePortType/DdsutPortType, PdmEventType)
- Fixed Grantlee template svc_translation.cpp.grantlee:
  - Changed {{ idl_enum.name }}_def:: to {{ idl_enum.name }}::
  - Fixed .underlying() calls for C++11 scoped enums (enum class)
- Removed generated files from repo (moc_*, *_dtc.h, *_ftc.h)

Validation:
- BUILD_RTI=ON: SUCCESS
- BUILD_RTI=OFF: SUCCESS
- C++17 standard maintained for RTI 7.7 compatibility
- Ubuntu 26.04 Docker environment verified

Remaining Warnings (expected):
- BgViewer, KDChart, KDReports, Poppler-Qt6 not found (optional features)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt5-before/dlbo/Lts/Services/ExerciseManagement/main_handler.h

@@ -0,0 +1,59 @@
+/**
+  * @RDE_HEADER@
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  */
+#pragma once
+
+#include <QObject>
+#include <memory>
+#include "dds_handler.h"
+#include "exm_db.h"
+#include "logger.h"
+#include "WebSocketInterface/websocket_interface_handler.h"
+#include <ngldb/db_service_handler.h>
+
+namespace DBAdministration
+{
+class ExerciseTableGenerator;
+}
+
+namespace ExerciseManagement
+{
+using DbHandler = NGLDB::DbServiceHandler<DatabaseInterface>;
+class HandlerExercise;
+class HandlerExercisePhase;
+
+class MainHandler : public QObject
+{
+  Q_OBJECT
+public:
+  explicit MainHandler(QObject *parent = nullptr);
+  ~MainHandler();
+
+  bool init(int domainId);
+  std::shared_ptr<HandlerExercise> exerciseHandler () const { return m_handlerExercise; }
+  std::shared_ptr<HandlerExercisePhase> exercisePhaseHandler () const{ return m_handlerExercisePhases; }
+  std::shared_ptr<DatabaseInterface> db() const { return m_dbHandler->db(); }
+  std::shared_ptr<DdsHandler> dds() const { return m_ddsHandler; }
+
+private:
+  bool initDbAdminstration();
+  bool initExerciseHandler();
+  bool initExercisePhaseHandler();
+  bool initWebSocketHandler();
+  void sendKeepAlive();
+
+private:
+  std::shared_ptr<HandlerExercise>      m_handlerExercise;
+  std::shared_ptr<HandlerExercisePhase> m_handlerExercisePhases;
+  std::shared_ptr<DdsHandler>           m_ddsHandler;
+  std::shared_ptr<DbHandler>            m_dbHandler;
+  std::shared_ptr<DBAdministration::ExerciseTableGenerator>     m_exTblGen;
+  std::shared_ptr<WebSocketInterface::WebSocketInterfaceHandler> m_websocketHandler;
+
+  NGL::INGLLogger                      &m_logger;
+
+};
+} // namespace ExerciseManagement