Other snapshots enhancements

[John-Gee]

Taken from #882

1- When extracting the snapshot, it'd be nice to know what % has been done so far/how much time left.

2- Can you not download to ~/snapshots but something more specific? That does not look clean to me nor am I keen on more folders in ~/ . Also is this location configurable in the config file? I have the space, but maybe others won't.

These are not as important with the smaller snapshots, unless you allow again unpruned ones as asked in #940 .

Thanks!