Feature request: estimate-template-cost

### Describe your idea/feature/enhancement

The AWS CLI offers a `estimate-template-cost` under `aws cloudformation`; however, since SAM uses Transforms, the ability to use AWS CLI on the built template is not possible. It would be great if SAM CLI supported a feature such that you could estimate the cost. Especially since the [output](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/cloudformation/estimate-template-cost.html#output) of `estimate-template-cost` is just a link to the pricing calculator. I realize that it might be counter intuitive since it is "serverless"; however, it would help in budget projections and proposals as well as for those more "fixed" style costs such as WAF ACL

### Proposal

I'd propose this be a new options such as: `sam estimate-cost` which would then, given the template.yaml generated by `sam build`, output a link to the pricing calculator with the appropriate resourced configured. The user of the tool can then, via the calculator, input their own values to further "dial-in" their cost estimates.

Things to consider:
1. Does the pricing calculator support all of the resources that SAM build would generate?
2. Will the pricing calculator allow a URL to be generated that allows for dynamic values? (i.e. expand the scope of the build.toml to accept specific throughput)