Improve the `edgedb restore` verbose output

[nervetattoo]

Currently this is the output pr block Block 107 processed: 923.72 MB restored I'd love to see a few more pieces: Block 107 processed: 923.72 MB restored (20%). 32 minutes remaining

Should be able to get a decent enough remaining time if calculated per tick. My experience is that the first blocks (50 or so) go are relatively fast so it would report a too optimistic number but thats fine as long as it is calculated per block.