fully parameterize the AZ configuration in the eksctl config

[brentley]

in: https://www.eksworkshop.com/030_eksctl/launcheks/

replace the hardcoded "a/b/c" AZs with AZ values from the current region.

[brentley]

declare -a azs=($(aws ec2 describe-availability-zones --query 'AvailabilityZones[].ZoneName' --output text))

then you can substitute into the config file: ${azs[0]} ${azs[1]} ${azs[2]}