Enable build with QT_DISABLE_DEPRECATED_UP_TO= current Qt version in the CI

While trying to enable builds with QT_DISABLE_DEPRECATED_UP_TO, I noticed that we have a lot of places where the proper deprecation warning is missing, so we still keep using the old API. In some other places the warning is explicitly silenced. All such places will result in hard compiler errors when building with QT_DISABLE_DEPRECATED_UP_TO >= the deprecation version.

Once we have the possibility to set QT_DISABLE_DEPRECATED_UP_TO as a configure parameter, we need to enable at least one build (ideally - one for each platform) with QT_DISABLE_DEPRECATED_UP_TO = Current Qt version, to make sure that we do the deprecation correctly. Otherwise this feature will never work as expected.

The scope of this task involves discussion with the CI team, and probably providing patches for them