Rewrite Arc-Script compiler in OCaml

[segeljakt]

This is a PR which adds another compiler for arc-script, written in OCaml (reusing code I wrote in a previous course I took, given by David Broman). In contrast to the Rust-compiler, this compiler is meant for quick experimental prototyping, mainly for research publications. It is not intended to be used by end-users. The following features are not a priority:

• Syntax - The compiler does not have a fancy parser/printer. Instead it just derives an S-Expression parser/printer for the AST. (Update: The parser is now at the same level as the Rust implementation and uses the Menhir parser generator)
• Performance - Performance tricks like replacing strings with integers is not a priority. The compiler will be entirely functional.
• Modules - A program is just a single file.
• Error handling - If it is possible I will maintain line information in the AST to track where errors occur but anything beyond that, such as error recovery, is probably not going to happen.
• User interface - LSP/REPL/CLI will not be supported. The compiler will just take a file, read, compile it, and produce output.

[segeljakt]

@frej just an FYI. I changed this PR so it goes into frej/WIP/receive-op.