Create a simple terminal-based example game

With a CLI crate in tree for our examples, this is a great opportunity to show off how Bevy can be used in less conventional contexts. This will make heavy use of a custom runner :)

Switched to google's `argh` crate for command line parsing. It's small, has only dependencies that we already have (syn, quote, serde, proc-macro2), and is still derive-based so brings most of the ergonomics we need. FromArgs has a blanket implementation for anything that implements FromStr. This means we have to implement FromStr for enums.

_Originally posted by @superdump in https://github.com/bevyengine/bevy/issues/9596#issuecomment-1698066683_