Update migration status and Dockerfile for Qt6/RTI 7.7 migration

- Updated MIGRATION_STATUS.md with current build status
- Added qtlocation and qtpositioning modules to Dockerfile
- Fixed RTI target collision issues in CMakeLists.txt
- Fixed Grantlee template namespace resolution for DTC generation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Entire-Checkpoint: 01M1BTYT8881P8P994NSAMC6R5

MIGRATION_STATUS.md

@@ -1,6 +1,6 @@
 # Qt5/C++11 to Qt6/C++17 Migration Status
 
-**Datum**: 2026-09-30  
+**Datum**: 2026-08-31  
 **Submodule Branch**: `feature/qt6-migration-basis-modules` @ d176b5e  
 **Docker-Image**: `migration-pipeline:ubuntu26.04`  
 **C++ Standard**: C++17 (⚠️ RTI 7.7 kompatibel nur mit C++17, NICHT C++23)