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

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)
