Convert spot-az column to availability-zone

[bra-fsn]

As #3 has pointed out, the current naming scheme is bad.
We should list US West (Los Angeles) in the us-west-2 region, as API endpoints are there.
Maybe the best solution for this would be to rename spot-az to availability-zone and handle the rest.
We should find mappings for other parameters, like the output of aws ec2 describe-availability-zones --all-availability-zones
gives:

{
            "State": "available",
            "OptInStatus": "not-opted-in",
            "Messages": [],
            "RegionName": "us-west-2",
            "ZoneName": "us-west-2-wl1-sfo-wlz-1",
            "ZoneId": "usw2-wl1-sfo-wlz1",
            "GroupName": "us-west-2-wl1",
            "NetworkBorderGroup": "us-west-2-wl1-sfo-wlz-1"
}

Other problems related to this include describe_spot_price_history doesn't seem to return spot prices for not-opted-in zones, so currently in order to fetch pricing data for them, we should opt-in for all, which may have other consequences.
Maybe we should use https://website.spot.ec2.aws.a2z.com/spotblocks-generic.js for fetching all prices, instead of relying on the API.