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/Viewer/LtsDataView/data_delegate.cpp

@@ -0,0 +1,31 @@
+/**
+ * @RDE_HEADER@
+ * Renders complex types from model data to text for views
+ * $Id$
+ * $HeadURL$
+ * $Author$
+ *
+ * Created by Mike Wille, NLE, 2020-09-09
+ */
+
+#include "data_delegate.h"
+
+#include <ngltools/ngltools_dtg.h>
+
+#include <QDateTime>
+
+
+namespace LtsDataView
+{
+DataDelegate::DataDelegate(QObject *parent)
+  : QStyledItemDelegate(parent)
+{}
+
+
+QString DataDelegate::displayText(const QVariant &value, const QLocale &locale) const
+{
+  if (value.type() == QVariant::Type::DateTime)
+    return DTG::toString(value.toDateTime());
+  return QStyledItemDelegate::displayText(value, locale);
+}
+} // namespace LtsDataView