Consider exporting Directory.list in cephfs package

[phlogistonjohn]

In a comment on #217 we have interest in having the list function exported. This is a convenience function that returns all entries in a directory in a single slice.

Alternatively, I had considered a ListN(int) version that could possibly split the difference between convenience and scalability.

[phlogistonjohn]

This was discussed recently over voice chat and we came to the conclusion that a very-thin list function is probably too "middle ground" outside of a few narrow use cases.

Rather, if we build on top of ceph_readdirplus_r we can get results that are similar (if not the same as) the Go os packages FileInfo result type. Using that we can more closely match the os-agnostic results that many Go programs expect to achieve.

[phlogistonjohn]

Closing this as a duplicate of #326 as that issue was filed by a non-maintainer and demonstrates some demand rather than my pure speculation.