AWS: Include Attached Storage in the total costs metric

[Pokom]

Background

For aws ec2, we export a metric cloudcost_aws_ec2_instance_total_usd_per_hour which computes the total cost of the instance in terms of CPU and Memory. This ignores any attached storage such as boot disks and volumes which can increase the cost from 10-20% depending on the type and size. In #240 a metric was introduced to calculate the cost of ebs volumes that are associated with EKS clusters.

Problem

For users that are not running EKS clusters, we should make it easier for them to compute the total cost of an ec2 instance without having to join the metrics. One way that we could do that is to roll in the total cost of an instance into the cloudcost_aws_ec2_instance_total_usd_per_hour metric.

Goals

• include attached storage costs in cloudcost_aws_ec2_instance_total_usd_per_hour metric