Qt6 Migration: Complete migration with DDS/RTI support and build validation

Major Changes:
- Merged latest Qt5 devel content from dlbo (292 files changed, 7 new dirs)
- Consolidated forward-declarations and include folders
- Removed unneeded modules per Niklas' repo check list

Build System Fixes:
- Fixed CMake VERSION_GREATER syntax in ParticipantManagement/CMakeLists.txt
- Added VLC packages (libvlc-dev, vlc-plugin-base) to docker_build.sh
- Added PostgreSQL dev packages (libpq-dev, postgresql-server-dev-all) to Dockerfile
- Fixed locale warnings (ANSI_X3.4-1968 → C.UTF-8)
- Fixed ArcGIS SDK path warnings when BUILD_ARCGIS=OFF

Code Generation Fixes:
- Fixed IDL enum collisions (PortType→CorePortType/DdsutPortType, PdmEventType)
- Fixed Grantlee template svc_translation.cpp.grantlee:
  - Changed {{ idl_enum.name }}_def:: to {{ idl_enum.name }}::
  - Fixed .underlying() calls for C++11 scoped enums (enum class)
- Removed generated files from repo (moc_*, *_dtc.h, *_ftc.h)

Validation:
- BUILD_RTI=ON: SUCCESS
- BUILD_RTI=OFF: SUCCESS
- C++17 standard maintained for RTI 7.7 compatibility
- Ubuntu 26.04 Docker environment verified

Remaining Warnings (expected):
- BgViewer, KDChart, KDReports, Poppler-Qt6 not found (optional features)

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

qt5-before/dlbo/Lts/Plugins/BuildingViewer/share/_README.txt

@@ -0,0 +1,3 @@
+The following files are identical to the ones used within the BuildingViewer SVN project (See folder BuildingViewer/source/viewerCtrl/).
+Since the BuildingViewer is compiled and started as an external application but data is exchanged between plugin and BuildingViewer the files for
+data handling are for now contained within this folder.

qt5-before/dlbo/Lts/Plugins/BuildingViewer/share/exccommands.h

@@ -0,0 +1,11 @@
+#pragma once
+
+/*
+ * Needs to be present respecitvely identical in plugin and buildingviewer project since all commands
+ * are evaluated on both sides.
+ */
+namespace BuildingViewer
+{
+enum AssetTypes {IndoorCamera = 200, IndoorCameraWithSpeaker, AnnouncementUnit, EffectGenerationUnit};
+enum BgViewerEvents {WidgetClosed, WidgetMaximized, WidgetMinimized, WidgetGotFocus, RoomNameClicked};
+}