Add support for EMR Integration. Autogenerated IAM role throws exception.

[atwoodjw]

When trying to deploy the stepFunction with an EMR integration, the following error is thrown.

User: arn:aws:sts::XXX:assumed-role/serverless-dev-XXX/XXX is not authorized to perform: elasticmapreduce:RunJobFlow on resource: arn:aws:elasticmapreduce:us-east-1:XXX:cluster/* (Service: AmazonElasticMapReduce; Status Code: 400; Error Code: AccessDeniedException; Request ID: XXX; Proxy: null)

I think this issue is similar to #385.

Amazon EMR is linked directly to a unique type of IAM role known as a service-linked role. For createCluster and createCluster.sync to work, you must have configured the necessary permissions to create the service-linked role AWSServiceRoleForEMRCleanup

https://docs.aws.amazon.com/step-functions/latest/dg/connect-emr.html