Qt6/RTI 7.7 Migration: Build-System und RTI-Integration fixes

CMake Build-System:
- NGL_ADD_SUBDIR_GUARDED() vor erstem Aufruf definiert (Zeile 38)
- Z/src wird VOR ENABLE_TESTING() eingebunden
- InfrastructureManagement an Anfang von Lts/Services CMakeLists.txt
- ALIAS Targets für RTI nur für existierende Libraries erstellt

RTI 7.7 Integration:
- generic_base.h: QMetaMethod Include hinzugefügt
- generic_data_reader.h: Template-Signatur auf 2 Parameter angepasst
  - detail::DataReaderImpl<Q> als Default-Template-Parameter

Qt6 Location Support:
- Dockerfile: qtlocation und qtpositioning Module hinzugefügt

Dokumentation:
- C++23 Inkompatibilität mit RTI 7.7 in copilot-instructions.md
- EXTERNAL_DEPENDENCIES.md Strategie dokumentiert

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

qt6-after/qt6-migrated-legatus/include/DDS/Generic/generic_data_reader.h

@@ -9,16 +9,28 @@
  */
 
 #ifdef BUILD_RTI
-// RTI DDS is available - include the real implementation
-#include <Lts/DDS/Generic/generic_data_reader.h>
+// RTI DDS is available - include the real implementation from RTI headers
+// DataReader is already defined in <dds/sub/subfwd.hpp> with signature:
+// template <typename T, template <typename Q> class DELEGATE = dds::sub::detail::DataReaderImpl>
+// class DataReader;
 #else
 // BUILD_RTI=OFF: Provide minimal stub definitions
 
 namespace dds {
 namespace sub {
+namespace detail {
+
+// Dummy delegate class to serve as default template parameter
+template<typename Q>
+class DataReaderImpl {
+    // Empty stub implementation
+};
+
+} // namespace detail
 
 // Forward declaration stub for DataReader
-template<typename T>
+// Must match RTI 7.7 signature for compatibility
+template<typename T, template <typename Q> class DELEGATE = detail::DataReaderImpl>
 class DataReader {
 public:
     // Minimal stub interface - add methods as needed by the codebase