Better estimates of how long a query might take

[cholmes]

Right now the CLI informs a user that a query is at least 5-10 seconds if they have a country_iso and 30-60 if they do not. But that's really just the minimum times, for small areas. It'd be better if we could provide more guidance - like if someone is trying to query a huge area then tell them it can minutes or hours, or even longer on a slow connection. I just did a decent sized area around Sao Paulo and it took 18 minutes to download 5.36 million buildings / 716.9 mb, and my connection is pretty fast.

This would likely need #32 to be sure that the user is actually requesting a large area if it's a large quadkey, since right now if it's a geojson that straddles a quadkey then it can look big but would still go pretty fast.

And ideally we'd do a good bit of testing to be able to give guidance - test really sparse areas in australia and dense areas in like India, and then also on different connections.

This is related to #31 - though this is probably a bit easier, as it's just guidance based on the size of the request, not trying to actually report what's happening. Though if that one is easier then this one may not be needed.