Wrappers for critical front-end components

[michkot]

We need access to program/functions/instructions details for proper development and debugging.

• Function: name, return type, argument types, argument Frontend IDs. Optional: "is intrinsic", linkage type
• Instruction: LLVM string rep, source info {file, line, column}
• Values = {Constants and Instructions}: source name (named register vs named stack variable?)

Implementation notes:
Generate map for values when creating CFG
Add "debugger mode" functionality -> retrieve all information on construction and cache it in the wrapper