Better debugging support on Windows

On Windows the Qt SDK is having two major options for development:

1. Microsoft Visual C++ with cdb.exe from Windows SDK
2. GNU GCC with gdb.exe

I just tested Qt Creator master (future 8.0 version) built against MSVC 2019 and MinGW 11.2.0, set a breakpoint in main.cpp before app.exec() call (all plugins and dlls were loaded at this point), and the warm (2nd debug run) results on my Ryzen 9 3950X were:

• gdb (version 11.2.0): 28.19s
• cdb: 15.37s

So cdb is almost twice as fast, and cdb is not the fastest debugger Microsoft has to offer.

I did the same test on a Ubuntu 20.04 Linux VM and got:

• gdb (version 9.2): 11.20s

Note that in all cases the "Debugging information" package was installed for the Qt 6.2.4 installation. 

Edit: I've installed Visual Studio 2019 community and tested the same setup:

• Visual Studio debugger: 7.45s