Handle hardlinks in package output

[andrewchambers]

I think when finalizing a package we should ensure its link count is 1. We really don't want to have files change underneath us via some funky link shenanigans.

[andrewchambers]

This may not be a real issue we need to worry about.

[akavel]

Would that preclude hardlinking as a deduplication (space conservation) strategy in hermes storage?

[andrewchambers]

I think my idea when I created this issue was the package cannot make links so the store can do it automatically yeah. Automatic hard linking/dedup is definitely on the agenda, I will make a ticket.