Ensure that simple sub folders for the main QML application work

QML supports folder import.

main.qml
Screen01.ui.qml
fsubfolder1/SomeSubComponent.ui.qml

Screen01.ui.qml would contain:

import QtQuick
import "fsubfolder1"

Item {
SomeSubComponent {
}
}

In this case 'fsubfolder1/SomeSubComponent.ui.qml' is not a different module (And there is no extra qmldir file). This means that SomeSubComponent.ui.qml can be added in the same cmakefiles.txt like Screen01.ui.qml. Ideally this simply works out of the box.