I have no idea what I meant with that.
Regions WIP

Turns out every call for spot price history must take a region, so we'll
have to call the command multiple times and marry the streams somehow
into one, probably by deduping headers and concatenating.
Just drop availability zones from input altogether

I somehow didn't notice the describe tool can take a region and will
present data for all AZs within. So really we just needed to run the
command once per zone and interleave the streams