Migrate from setuptools to hatch

[Yonghui-Lee]

Migrate from the legacy setuptools and versioneer to hatch. This aligns the project with modern Python packaging standards.

Key Changes

Build System & Versioning

• Migrate to Hatch: Switched the build backend to hatchling and enabled hatch-vcs for dynamic versioning based on Git tags.
• Consolidate Configuration: Added project metadata, dependencies, and tool configurations to pyproject.toml.

Cleanup of Legacy Files

• Remove setup.py: Dropped the legacy installation script in favor of declarative configuration in pyproject.toml.
• Remove Versioneer: Deleted versioneer.py and the generated gcsfs/_version.py.
• Remove MANIFEST.in: Hatch automatically handles file inclusion, making this file redundant.
• Remove .isort.cfg: Configuration has been moved to pyproject.toml.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.03%. Comparing base (5596df9) to head (0299219).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #809      +/-   ##
==========================================
+ Coverage   79.55%   85.03%   +5.48%     
==========================================
  Files          16       15       -1     
  Lines        3042     2680     -362     
==========================================
- Hits         2420     2279     -141     
+ Misses        622      401     -221     

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[zhixiangli]

Could you please verify that the ci.yml, benchmarks-cloudbuild.yaml, and cloudbuild/e2e-tests-cloudbuild.yaml files are still functional?

[Yonghui-Lee]

Could you please verify that the ci.yml, benchmarks-cloudbuild.yaml, and cloudbuild/e2e-tests-cloudbuild.yaml files are still functional?

I have run github ci, could build e2e tests and cloud build benchmark. The results look good to me.