* Rename `wit-bindgen-gen-guest-rust` to `wit-bindgen`
This commit creates a crate called `wit-bindgen` to be used from Rust.
While the name `wit-bindgen-gen-guest-rust` makes sense in the context
of other generators when using it specifically from Rust I think it
makes more sense to have the crate simply called `wit-bindgen` for
integration since the only context that name is used within is guest
bindings generator for Rust code.
* Add release CI automation for `wit-bindgen`
This is cobbled together from the `wasm-tools` and `wasmtime`
repositories and the idea is:
* A `publish.rs` script is added for managing versions and publication
to crates.io.
* Tags will upload binaries to GitHub releases
* CI is added for binary release builds of the CLI
* Fix copy/paste error
