[Feature] - Support Current Core code generation functionality on LLVM 20

[smaillet]

Re-work current functionality of code generation on LLVM20 (Or at least as much as is still supported)

Describe the solution you'd like
Current code generation works against LLVM 20 core libraries.

Describe alternatives you've considered
None

Additional context
LLVM10 is now rather old (and so is this code base) time for a major update/overhaul)