Allow disabling SetProcessDPIAware() call

Add Windows-specific wxMSWDisableSettingHighDPIAware() function then can
be called before startup (i.e. wxEntry() call) to disable wxWidgets'
handling of DPI awareness. This is useful for code embedded in non-wx
applications as well as for purely wx application that are not
HiDPI-ready (although the latter has the option of forcing
dpiAware=false in the manifest).

See also https://groups.google.com/d/msg/wx-dev/Z0VpgzCY34U/f1FfPqGDppMJ
and #16116.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@78406 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/app.h

@@ -1089,7 +1089,11 @@ int wxEntry(int& argc, wxChar** argv);
              }
              @endcode
 
+    @onlyfor{wxmsw}
+
     @header{wx/app.h}
+
+    @see wxMSWDisableSettingHighDPIAware()
 */
 int wxEntry(HINSTANCE hInstance,
             HINSTANCE hPrevInstance = NULL,