[FR] nREPL integration

[glyh]

In the LISP community there's a workflow called conversational development. Basically you can type your code inside a buffer, and send to a live REPL to see what happen, and modify the code on demand.

A lot of toolings are built just to tighten this workflow loop (write - test - fix): sly, cider.

Since we have utop as OCaml's REPL, we can very much just implement nREPL protocol and have some of their nice debugging assistance as well. Of course this requires editor side's support, I plan to do this support in conjure for neovim.

I would like to contribute, but I want to know about the opinions of the maintainer as this would likely to become a switch on utop so it run as an nREPL.

Thanks :)