Typed SIR

[nau]

Modify Scalus compiler plugin to extract type information and put it into generated SIR.

It's going to be System Fw types. Something like this:

enum Type:
  case TyCon(...)
  case TyVar(v: String)
  case TyLabAbs(v: String, body: Type)
  case TyApply(f: Type, a: Type)

[rssh]

basic implementation sketch in https://github.com/rssh/scalus/tree/typed-sir (WIP, not yet compiled)