Implement `clsid!(..)` attribute

[Rantanen]

Interfaces and dependent types can currently be shared through common crates between COM client and server.

CLSID is defined through #[com_class(..)] attribute, which exists only in the COM server.

We should support clsid!(..) macro that is able to define public global clsids in a common crate and a way for #[com_class(..)] to use those class ids. The class ids probably need to be generated for both automation and raw type systems.

[Rantanen]

Mistakenly closed

[sancarn]

In a similar vein - ProgID would be useful.