* Add 'ipfs repo migrate' command
This PR replaces #7658 that was originally contributed by zaibons, in order to move code into a branch and avoid some CI problem.
The command allows the user to run the repo migration without starting the daemon.
resolves#7471
* return non-ErrNeedMigration errors from fsrepo.Open()
Co-authored-by: Gus Eggert <gus@gus.dev>