Implement runtime IID calculation for parametric interfaces via const fn

[Boddlnagg]

First step towards const fn evaluation. Changes:

• Change ComIid trait to return by value (should be changed to an associated const before merging this)
• Add fullname strings to RT_CLASS, RT_STRUCT & RT_ENUM
• Add dependency on uuid crate ... we need to see whether they will support const fn evaluation eventually

Finishing this depends on at least https://github.com/rust-lang/rfcs/pull/2632