Qt6 Migration: BUILD_RTI guards und CMake fixes

- BUILD_RTI conditional compilation für RTI Connext DDS dependencies
- Namespace fixes in core_dtc.h (Core:: → DDS::Core::)
- CMakeLists.txt: BUILD_RTI option und conditional dependencies
- Handler minelayer: namespace closing mit BUILD_RTI guard
- Build erfolgreich mit BUILD_RTI=OFF validiert

Signed-off-by: Torsten Wierschin <torsten.wierschin@life-maps.com>

qt6-after/qt6-migrated-legatus/Lts/Services/AudioVideoManagement/exercises_handler.cpp

@@ -55,7 +55,7 @@ private:
 ExercisesHandler::ExercisesHandler(MainHandler *mainHandler) : m_mainHandler(mainHandler)
   , m_triggerAvUpdateTimer(new QTimer(this))
   , m_assetAssignmentManager(AssetAssignmentManager::create(mainHandler->ddsHandler()->ismDtc())),
-    m_logger(NGL::NGLLoggerBootstrap::getLogger()) {
+    m_logger(NGL::NGLLoggerBootstrap::getNGLRootLogger()) {
   m_triggerAvUpdateTimer->setSingleShot(true);
   m_triggerAvUpdateTimer->setInterval(1000);
   connect(m_triggerAvUpdateTimer, &QTimer::timeout,