Add support for MSI start menu shortcut

[AceofSpades5757]

WiX Toolset has the capabilities of adding a shortcut to the Start Menu on Windows, but I don't see any option to include this during building.

This would add a lot of value to installations where the user is trying to find the program they just installed on Windows.

WiX Toolset - How To: Create a Shortcut on the Start Menu

[andrewleech]

FYI I've added an implementation for this in https://github.com/indygreg/PyOxidizer/pull/714