Implement import syntax / instance generation via TH
The initial import syntax might be possible as just Haskell EDSL, but since it needs to use TH anyway, perhaps best as a new syntax for a TH quasi quoter.
It should then result in a description of all assemblies referenced and namespaces to be imported.
From the reference / import definition, TH can be used to generate each instance, querying the actual assemblies via reflection for all the information it needs. TH can do this because it actually allows IO, though race conditions and/or multithreading might make compilation unsafe without care.