- Converts previous `DeclBlock` into `Atom`'s to also make them compatible when
the rest of zlwd gets upstreamed and we can link with other object files.
- Resolves function signatures and removes any duplicates, saving us a lot of
potential bytes for larger projects.
- We now create symbols for each decl of the respective type
- We can now (but not implemented yet) perform proper relocations.
- Having symbols and segment_info allows us to create an object file
for wasm.