feat: support UnixFS 1.5 file mode and modification times

[kstuart]

Adds support for storing and retrieving file mode and last modification time.

Support added to:

• [X] Files
• [X] LinkFiles
• [X] Webfiles
• [X] Directories
• [X] Tar Archives

When the TAR archive (headers) include a file mode or modification time, the extractor will restore that metadata when supported for the underlying filesystem.

The Golang runtime currently does not support changing the times on a symlink, for Linux and some BSDs a custom solution has been implemented, for Darwin this is not the case so when copying a symlink to the filesystem the last modification time is not updated. Since for concrete files and directories stored modes and modification times are faithfully restored to the filesystem this should not be a breaking issue, a similar solution to that implemented for Linux/BSDs is likely implementable by a developer with access to a Darwin platform.

Replaces PRs:

• https://github.com/ipfs/go-ipfs-files/pull/31
• https://github.com/ipfs/tar-utils/pull/11

Relates to https://github.com/ipfs/kubo/issues/6920

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[codecov[bot]]

Codecov Report

Merging #34 (7161a2f) into main (c444cbb) will increase coverage by 2.19%. The diff coverage is 78.01%.

:exclamation: Current head 7161a2f differs from pull request most recent head 77cdc80. Consider uploading reports for the commit 77cdc80 to get more accurate results

@@            Coverage Diff             @@
##             main      #34      +/-   ##
==========================================
+ Coverage   63.75%   65.94%   +2.19%     
==========================================
  Files          32       30       -2     
  Lines        1694     1856     +162     
==========================================
+ Hits         1080     1224     +144     
- Misses        477      486       +9     
- Partials      137      146       +9     

Impacted Files	Coverage Δ
files/serialfile.go	63.72% <0.00%> (-2.61%)	:arrow_down:
tar/extractor.go	51.04% <51.31%> (-0.36%)	:arrow_down:
tar/util_posix.go	60.00% <60.00%> (ø)
files/multipartfile.go	83.51% <78.84%> (-2.41%)	:arrow_down:
files/util.go	75.86% <89.47%> (+25.86%)	:arrow_up:
files/tarwriter.go	83.52% <93.54%> (+10.91%)	:arrow_up:
files/linkfile.go	64.00% <100.00%> (+24.00%)	:arrow_up:
files/multifilereader.go	85.45% <100.00%> (+3.43%)	:arrow_up:
files/readerfile.go	77.08% <100.00%> (+10.41%)	:arrow_up:
files/slicedirectory.go	80.32% <100.00%> (+6.99%)	:arrow_up:
... and 1 more

... and 3 files with indirect coverage changes

[zacharywhitley]

Any status on where this is? It seems to be stalled.

[kstuart]

@zacharywhitley, unfortunately I don't think there's any real interest in this feature; This has been awaiting review for some time, and the completed https://github.com/ipfs/kubo/issues/6920 PRs prior to the refactoring met the same fate.

[gammazero]

Replaced by PR #653