CMake: Allow individual projects to switch default build configuration to 'Release'

It would be helpful if some Qt examples would be configured with 'Release' build configuration by default.

Use case

We have some Qt application examples that are heavy on visuals and animations. They work fine for Release builds, but are rather sluggish for Debug builds. To leave a good 'first' impression, it would be therefore benefical if such examples would be build as Release by default if opened in Qt Creator.

Implementation Ideas

Could this be done by shipping CMake Presets by setting a CMAKE_BUILD_TYPE? THe issue is that we can't hard-code the exact Qt version / name though ...