[Development] Removal of configure.json files

[Joerg Bornemann]

Hi,

The CMake build in Qt 6 uses configure.cmake files that have been 
converted from the configure.json files. If you've changed a 
configure.cmake file you probably have been asked to change 
configure.json too - to keep the content in sync.
This modus operandi is tedious and error-prone.

At this point in time, we're convinced that all necessary information 
was properly converted and the configure.cmake API is mature enough and 
matching the old configure.json approach feature-wise.

Therefore we would like to remove the configure.json files from all 
repositories, except the ones that need to build with Qt5 and Qt6.

We would like to do this removal for 6.2 already, because this would 
greatly simplify cherry-picks of configure.cmake changes from dev.

If you have any objections, shoot!


Cheers,

Joerg

Tracking issue: https://bugreports.qt.io/browse/QTBUG-89536