Prune to show progress

After enumerating snapshots and chunks to be deleted Prune knows exactly how many chunks it needs to process, so it should be showing the progress.

Case in point: I’m running prune -exclusive -exhaustive now on a google drive storage (after manually deleted over a hundred of orphaned snapshots) and it is processing about 1 chunk per second for the past 18 hours and I have no idea for how long more it will continue…