Rework how irust server works

[sigmaSd]

IRust can spawn a server useful for editor plugins to send input, but its currently really tailored to a custom plugin I wrote https://github.com/sigmaSd/irust-vim-plugin

-> The server currently receives input from the client and run it on the repl

I think a better way is to make this a server that listens to input and then sends back the output to the client and the client gets to decide what it wants to do with it.

This would make easily integrate-able with something like https://github.com/Olical/conjure

Another option is to wait for crossterm-rs/crossterm#711 this will allow for the repl to receive stdin with normal keys (like every other repl) and so we wouldn't need the server workaround