CMake Build: Instruct CMake to create the fileApi json structure for IDEs

The CMake configuration process of QtBase, or of a Qt6 super build can take a while, it would be helpful if this time could be reduced to zero when importing the build in Qt Creator (or other IDE that supports CMake fileApi).

If the CMake build system would make sure that in the build directory there will be the following file structure (<build_dir>/.cmake/api/v1/query)

└───.cmake
    └───api
        └───v1
            └───query
                    cache-v2
                    cmakeFiles-v1
                    codemodel-v2

The files are 0 bytes in size.

This way Qt Creator could import the build and load the CMake project very fast, thus having a better user experience.