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/Tools/QLedLine/Test/props.cpp

@@ -0,0 +1,47 @@
+#include <QColorDialog>
+
+#include "props.h"
+#include "ui_props.h"
+
+Props::Props(QWidget *parent) : QWidget(parent)
+  , m_ui(new Ui::Props)
+{
+  m_ui->setupUi(this);
+
+  connect(m_ui->slFlashTime,   &QSlider::valueChanged,  this, &Props::flashTimeChanged);
+  connect(m_ui->leInput,       &QLineEdit::textChanged, this, &Props::textChanged);
+  connect(m_ui->pbTextVisible, &QPushButton::clicked,   this, &Props::showText);
+  connect(m_ui->pbColor,       &QPushButton::clicked,   this, &Props::onPbColorClicked);
+}
+
+Props::~Props()
+{
+  delete m_ui;
+}
+
+int Props::lineIndex() const
+{
+  return m_lineIndex;
+}
+
+void Props::setLineIndex(int lineIndex)
+{
+  m_lineIndex = lineIndex;
+  m_ui->lbTitle->setText(tr("%1. Line").arg(m_lineIndex));
+}
+
+void Props::onPbColorClicked()
+{
+  m_color = QColorDialog::getColor(m_color, this, tr("Farbe wählen"));
+  emit colorChanged(m_color);
+}
+
+QString Props::inputText() const
+{
+  return m_ui->leInput->text();
+}
+
+void Props::setInputText(const QString &inputText)
+{
+  m_ui->leInput->setText(inputText);
+}