_bootstrap_python: Fix execution on windows disabling site import

This workaround the lack of `sys.winver` attribute addressing the following
error:

```
 Generating C:/path/to/Python-3.11.12/Python/deepfreeze/deepfreeze.c
CUSTOMBUILD : Fatal Python error : init_import_site: Failed to import the site module [C:\path\to\pycbs-3.11-build\CMakeBuild\libpython\libpython-shared.vcxproj]
  Python runtime state: initialized
  Traceback (most recent call last):
    File "C:\path\to\pycbs-3.11-build\Lib\site.py", line 626, in <module>
      main()
    File "C:\path\to\pycbs-3.11-build\Lib\site.py", line 612, in main
      known_paths = addusersitepackages(known_paths)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "C:\path\to\pycbs-3.11-build\Lib\site.py", line 350, in addusersitepackages
      user_site = getusersitepackages()
                  ^^^^^^^^^^^^^^^^^^^^^
    File "C:\path\to\pycbs-3.11-build\Lib\site.py", line 337, in getusersitepackages
      USER_SITE = _get_path(userbase)
                  ^^^^^^^^^^^^^^^^^^^
    File "C:\path\to\pycbs-3.11-build\Lib\site.py", line 302, in _get_path
      ver_nodot = sys.winver.replace('.', '')
                  ^^^^^^^^^^
  AttributeError: module 'sys' has no attribute 'winver'
```

Author: jcfr

Programs/_bootstrap_python.c

@@ -76,6 +76,9 @@ main(int argc, char **argv)
     // add current script dir to sys.path
     config.isolated = 0;
     config.safe_path = 0;
+#ifdef MS_WINDOWS
+    config.site_import = 0;
+#endif
 
 #ifdef MS_WINDOWS
     status = PyConfig_SetArgv(&config, argc, argv);