Add MSVC version to qtpaths -query output

The Qt vscode extension uses the qtpaths -query output to generate kits. To generate MSVC kits, the extension parses the qt.conf file to obtain MSVC version info. Instead of doing that, we can add version info to qtpaths -query.

Possible -query output

...
QT_MSVC_MAJOR_VERSION:19
QT_MSVC_MINOR_VERSION:39
QT_MSVC_PATCH_VERSION:33519
...