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/Proxies/TrainingAreaBase/position_handler.cpp

@@ -10,7 +10,7 @@ using namespace TrainingAreaBase;
 
 PositionHandler::PositionHandler(MainHandler *mainHandler) : QObject()
   , m_mainHandler(mainHandler),
-    m_logger(NGL::NGLLoggerBootstrap::getLogger()) {}
+    m_logger(NGL::NGLLoggerBootstrap::getNGLRootLogger()) {}
 
 bool PositionHandler::init()
 {