feat(fs/unstable): add chown and chownSync

[jbronder]

This PR adds chown and chownSync APIs to @std/fs package which are intended to mirror the Deno.chown and Deno.chownSync functions.

Towards #6255.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 14 lines in your changes missing coverage. Please review.

Project coverage is 95.03%. Comparing base (9d765df) to head (d8173b4).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
fs/unstable_chown.ts	60.00%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6552      +/-   ##
==========================================
- Coverage   95.06%   95.03%   -0.03%     
==========================================
  Files         576      577       +1     
  Lines       43370    43405      +35     
  Branches     6472     6475       +3     
==========================================
+ Hits        41231    41252      +21     
- Misses       2098     2112      +14     
  Partials       41       41              

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[kt3k]

Nice test case 👍

[kt3k]

LGTM. Thanks!