Feature Request: Add policies for running Distributed Maps in State Machines (Step Functions)

[davidjb]

Currently, the only policies in the library are for starting executions StepFunctionsExecutionPolicy and StepFunctionsExecutionPolicy_v2 (https://github.com/aws/serverless-application-model/blob/develop/samtranslator/policy_templates_data/policy_templates.json#L2332).

Could IAM policies for running and using Distributed Maps be added to the policy library? This includes:

• Running Distributed Maps (https://docs.aws.amazon.com/step-functions/latest/dg/use-dist-map-orchestrate-large-scale-parallel-workloads.html#dist-map-permissions)

  {
    "Version": "2012-10-17",
    "Statement": [
      {
        "Effect": "Allow",
        "Action": [
          "states:StartExecution"
        ],
        "Resource": [
          "arn:aws:states:region:accountID:stateMachine:stateMachineName"
        ]
      },
      {
        "Effect": "Allow",
        "Action": [
          "states:DescribeExecution",
          "states:StopExecution"
        ],
        "Resource": "arn:aws:states:region:accountID:execution:stateMachineName:*"
      }
    ]
  }

• ItemReader for S3 (https://docs.aws.amazon.com/step-functions/latest/dg/input-output-itemreader.html#itemreader-iam-policies)

• ResultWriter for S3 (https://docs.aws.amazon.com/step-functions/latest/dg/input-output-resultwriter.html#resultwriter-iam-policies)