shells/schemesh: New port: Unix shell, and LISP repl

Schemesh is an interactive shell scriptable in Lisp.

It is primarily intended as a user-friendly Unix login shell,
replacing bash, zsh, pdksh etc.

As such, it supports interactive line editing, autocompletion, history
and the familiar Unix shell syntax: it can start commands, including
redirections, pipelines, job concatenation with ; && ||, groups
surrounded by { }, subshells surrounded by [ ], and manage
foreground/background jobs.

WWW: https://github.com/cosmos72/schemesh