QmlProject: Add warning for old projects

Task-number: QDS-13705
Change-Id: Ief8af59611d71e46bf6cfa5fd171e759c5c82fdc
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmlprojectmanager/qmlprojectexporter/cmakewriter.cpp

@@ -38,6 +38,14 @@ CMakeWriter::Ptr CMakeWriter::create(CMakeGenerator *parent)
     if (float version = versionString.toFloat(&ok); ok && version > 4.4)
         return std::make_unique<CMakeWriterV1>(parent);
 
+    CMakeGenerator::logIssue(
+        ProjectExplorer::Task::Warning,
+        "The project was created with a Qt Design Studio version earlier than Qt Design Studio "
+        "4.5. Due to limitations of the project structure in earlier Qt Design Studio versions, "
+        "the resulting application might not display all the assets. Referring to "
+        "assets between different QML modules does not work in the compiled application.",
+        buildSystem->projectFilePath());
+
     return std::make_unique<CMakeWriterV0>(parent);
 }