remove git modules and use the git link

[JunkyDeveloper]

Type of change

• Bug fix
• New feature
• Breaking change
• Refactor / code cleanup
• Performance improvement
• Chore / tooling
• Documentation

Summary

from git module to git in cargo, idk why the git module path was choosen

Testing

cargo build

[Purdze]

The submodule was intentional so it can't go in as is

ci's steel cache keys off git -C third_party/SteelMC rev-parse HEAD and caches the generated source in that directory and with the submodule gone, that step fails silently (fatal: cannot change to 'third_party/SteelMC' in the Ubuntu log) and the cache now saves under an empty key, steel-generated

dependabot bumps steel through the gitsubmodule ecosystem, which does nothing once the submodule is removed.

the path dependency lets us patch steel locally and build right awayand a git dependency needs a [patch] override for that, which makes working on steel fixes slower

If we do switch later, it would also need the full 40-char SHA in rev (a short rev makes cargo fetch every ref), a single [workspace.dependencies] entry rather than four copies, the ci cache reworked to point at the cargo git checkout, and the docs updated: README, CONTRIBUTING, THIRD_PARTY_LICENSES, and exclude in the root Cargo.toml

[JunkyDeveloper]

Ok thanks for the feedback and is a good design