Improve resilvering icon & pop-up information
When disks are silvering, I'd like to see the pop-up information box when clicking the rotating arrows icon to have two extra functions from what it has in RC1:
1) Show the estimated time to completion, along with the percent complete. (This estimated time can be seen from the console with a `zpool status` command, for example. So it would be nice to expose that in the GUI.)
2) a) Have the pop-up update "live" to show percent complete and time remaining; OR
b) Instead of showing "time remaining", show date/time of estimated completion, like if it has 2 hours left and it's 7:47PM on the 24th, something like "Complete around 24-Oct-2018 21:47"; OR
c) Have the tooltip for the resilvering also show this information. It would be nice to just hover over the spinning icon to see the status instead of needing to click it if I just want quick info.