Switch to using cargo-bitbake to generate the recipe and bump versions at the same time.
The old cargo.bbclass had no users in meta-rust and had lots of problems (not least of which was lots of duplicated lines with cargo_util.bbclass). Delete the old cargo.bbclass and replace it entirely wiht cargo_util
rustfmt is a Rust package to format Rust code. This package is being used as an example of building a crate in Yocto with Cargo.
