Fix uninstall link creation in installscripts

Move the uninstall link creation from qt.tools to qt.tools.maintenance
as the uninstall shortcut needs maintenance tool anyways. And to keep
all MaintenanceTool related functionality in the same component.

Change-Id: I2312935540f9b70b4c28d2317824a8417126ed6f
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>