refactor: unify to filesystem in rspack_core

[hardfist]

Summary

It's not necessary to distinguish different filesystem trait in rust side, which only cause maintenance burden, we just need to distinguish input & output & intermediate filesystem in ThreadsafeNodeFS

Checklist

• [ ] Tests updated (or not required).
• [ ] Documentation updated (or not required).

[netlify[bot]]

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[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #8522 will not alter performance

_{Comparing yj/unify-filesystem (a247ef9) with main (eb12150)}

Summary

✅ 1 untouched benchmarks