Replaces PR #34 written by @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:
- ipfs/go-ipfs-files#31
- ipfs/tar-utils#11
- #34

Relates to ipfs/kubo#6920

- Fix windows test

…658)

* feat: Support UnixFS mode and modification times in ipld dag and mfs

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

Support added to:
- Files
- LinkFiles
- Webfiles
- Directories

Tar archives are supported by the parent branch.

Fixes #660