Add ELF loading information

[ailrst]

This paper describes work formalising linking/ELF loading https://github.com/rems-project/linksem/blob/master/papers/oopsla-elf-linking-2016/oopsla-elf-linking-2016.pdf

Their ocaml library (that is at least partly code-extracted from the formal semantics?) seems fairly straightforward to use, we should load the elf table information this way and dump it into BASIL as JSON or similar. https://ocaml.org/p/linksem/0.8/doc/Elf_file/index.html

The functionality to produce memory images to begin execution is worth looking into.