Codegen for IPropertyBag2 and its friends

[hez2010]

This is a follow-up to #1674.

It seems that we still need to introduce the support for IPropertyBag2, tagPROPVARIANT and tagPROPBAG2, otherwise it can be hard to use. For example, https://learn.microsoft.com/en-us/windows/win32/wic/-wic-creating-encoder#tiff-encoding-example

Those types are located in oaidl.h and ocidl.h.

Is there any way to only include the types we actually need without introducing the whole bunch of unnecessary dependencies?

Originally posted by @hez2010 in #1674 (comment)

[Perksey]

You could add these headers and exclude everything but these types, but really we need support for that in the generator.

Happy for whatever is practicable here.