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/RoutingServiceNG/data_writer_task.h

@@ -11,8 +11,10 @@
 #include <queue>
 #include <mutex>
 #include <condition_variable>
-#include <DDS/Routing/routing_plugin.h>
 
+#if BUILD_RTI
+#include <DDS/Routing/routing_plugin.h>
+#endif
 #include "logger.h"
 
 namespace RoutingService