AWS::EMR::Cluster - ManagedScalingPolicy

## 1. Title

**AWS::EMR::Cluster-ManagedScalingPolicy**

## 2. Scope of request

In EMR 5.30.0 (and 6.1.0), EMR introduced a new "managed autoscaling" feature. This can be used by specifying a [ManagedScalingPolicy](https://docs.aws.amazon.com/emr/latest/APIReference/API_RunJobFlow.html#EMR-RunJobFlow-request-ManagedScalingPolicy) property when making a RunJobFlow API call (or can be manually set after the fact)

## 3. Expected behavior

* When a cluster resource is created, it should launch the cluster with the specified ManagedScalingPolicy settings in place.
* When updated, the managed scaling limits should be updated on the existing cluster. (Assuming no other changes, this shouldn't require replacement, I think.)

## 4. Suggest specific test cases

* Ensure clusters can launch with managed scaling enabled.
* Ensure you can use properties like !Ref within the managed scaling policy.
* Ensure the correct behavior occurs on older EMR releases that don't support this feature.

## 5. Helpful Links to speed up research and evaluation

Besides the `RunJobFlow` documentaiton linked to above, review the [Managed Scaling documentation](https://docs.aws.amazon.com/emr/latest/ManagementGuide/emr-managed-scaling.html).

## 6. Category (required) - Will help with tagging and be easier to find by other users to +1

7. Analytics (Athena, EMR, Glue,...)

## 7. Any additional context (optional)