Feature: Add a "cost" subcommand

[ejholmes]

CloudFormation has an EstimateTemplateCost API, which you can pass a CloudFormation template, and get back a URL to the cost calculator. It'd be kinda cool if stacker could automate this a bit, with a cost subcommand or something.

[xiaket]

Just my two cents here:

I was looking at cost management these days, and I must say the estimate template cost API is not very effective. The API will redirect you to a page and the calculation is done on the frontend by javascript. I would say merely giving out this external URL would not be really useful in automation, because a direct number is not provided, and given that the price of AWS resources is ever-changing, the URL will not really freeze the estimation down.

The alternative is, analyse the resource usage in the template and get the price using the pricing API. I must say this is a tedious job...