This MR adds a very basic implementation of `IPropertyDescription` for system defined properties (i.e, the ones in <propkey.h>). This is needed to support the [`Properties`](https://learn.microsoft.com/en-us/uwp/api/windows.devices.enumeration.device...) method for `IDeviceInformation` in Windows.Devices.Enumeration (!6874).
-- v6: dlls/propsys: Implement IPropertyDescription for several known system properties. dlls/propsys: Add IPropertyDescription stub for system defined properties.