- these tools shouldn't need access to coremem internals.
- lifting them out reduces some dependencies in coremem-the-library.
- separation allows faster iteration in the coremem library while
temporarily breaking the post-processing tools (specifically,
those tools could take deps on a specific coremem version and thereby
we split the update process into two, smaller steps).
this solves an issue in the Nix build, where managing multiple
Cargo.lock files is otherwise tricky. it causes (or fails to fix?) an adjacent issue where
the spirv builder doesn't seem to have everything it needs vendored.
