Implement runtime-versioner audit tool (#3332)

This PR implements a build tool to audit runtime crate versions as part
of CI and release. If a runtime crate doesn't have the special
`0.0.0-smithy-rs-head` version number, then it is assumed to be
independently versioned, and the audit tool will verify it is version
bumped when any changes are made to it.

Given that there isn't a complete/reliable semver checking tool for Rust
yet, this tool isn't smart. It will rely on devs to correctly bump the
version number when that is done.

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