Making QML modules both for Qt5 and Qt6

[Halla Rempt]

Because we can't give up on Qt5 builds of Krita for now (there are some big 
problems with gpu acceleration and tablet support we are investigating), we'll 
need to release the next major release of Krita for both Qt5 and Qt6.

I'm trying to add QML modules right now, but I'm only succeeding on Qt6: 
https://invent.kde.org/graphics/krita/-/merge_requests/2346

This is what I have:

ecm_add_qml_module(kritaqml
    URI org.krita.qml
    VERSION 1.0
    SHARED
    GENERATE_PLUGIN_SOURCE
)

target_sources(kritaqml
    PUBLIC
        SvgTextLabel.cpp
)

target_link_libraries(kritaqml
    PUBLIC
        kritaui
    PRIVATE
        Qt::Quick
)

ecm_target_qml_sources(kritaqml SOURCES
    qml/DoubleSpinBox.qml
)

ecm_finalize_qml_module(kritaqml DESTINATION ${KDE_INSTALL_QMLDIR})

install(TARGETS kritaqml ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})


And I'm not sure how I should rewrite this for Qt5. Can anyone help me, please?

Cheers,

Halla