Migrate Qt5 to Qt6

[mjcarroll]

Tracking issue for tasks required to migrate from Qt5 to Qt6.

• CMake Updates
• Update MinimalScene for new APIs getting native access to VkImage and Metal equivalent.
• QtGraphicalEffects is deprecated and has some incompatibilities: https://doc.qt.io/qt-6/qtgraphicaleffects5-index.html
• QRegExp is deprecated: https://doc.qt.io/qt-6/qregexp.html

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Environment: Ubuntu Noble + Gazebo Ionic + Qt6 + #596 + gazebosim/gz-sim#2305
Initial test: gz sim minimal_scene.sdf

Goals

1. Make Gz Ionic work with Qt5/Qt6
2. Backport Qt5 changes to Harmonic

Tasks

• Update our gz gui CI action to use Ubuntu Noble.
• Forward port gz-qui8 to main.

Ideas

• Load our qml codebase into Qt Creator / GammaRay to detect issues.

Current list of issues:

• GzSpinBox. Replace it with a textbox widget.
• TreeViewStyle not available in Qt6 qml .
• Review if QtQuick.Controls 1.x is used and identify the replacement if any.
• [GUI] [Err] [Gui.cc:326] Failed to instantiate custom drawer, drawer will be empty.
• (fixed) Confirm if there's a segfault when running gz sim shapes.sdf or gz sim minimal_scene.sdf.
• Propagate the changes made in gz-gui to compile plugins as modules.
• 3D scene window not working. Minimal example to load a 3D scene:
  * https://doc.qt.io/qt-6/debug.html
  * There's a useful example in gz-rendering: examples/simple_demo_qml .
  * 1st test: Load MinimalScene only and create a <scene> element within <world> to change the background color.
  * 2nd test: Create an SDF with MinimalScene (gz-gui) and SceneManager (gz-sim).

[mjcarroll]

Compatible changes between qt5+qt6: #598

[mjcarroll]

Clazy checks: #584

[mjcarroll]

Bulk of the migrations for gui: #596

[azeey]

Here's the list of qt6 packages I needed to install:

• qml6-module-qt-labs-folderlistmodel
• qml6-module-qt-labs-platform
• qml6-module-qt-labs-settings
• qml6-module-qtcharts
• qml6-module-qtpositioning
• qml6-module-qtqml-models
• qml6-module-qtquick-controls
• qml6-module-qtquick-dialogs
• qml6-module-qtquick-layouts
• qml6-module-qtquick-templates
• qml6-module-qtquick-window
• qml6-module-qtquick
• qt6-base-dev
• qt6-declarative-dev
• libqt6quickcontrols2-6
• qml6-module-qtcore
• qml6-module-qtqml-workerscript
• qml6-module-qt5compat-graphicaleffects
• libqt6svg6

[azeey]

I've added a fix in the gz-sim branch gazebosim/gz-sim@a2652ac which should help with the communication between the server and GUI ECMs. With that, I see glimmers of hope :)
Screen recording 2024-07-16 14.18.43.webm

[caguero]

I was able to visualize the 3D screen even without your changes. It was hidden at the very left covered by other collapsed window plugins.