Option to not deregister prior AWS Batch Job Definition revisions

### Name of the resource

AWS::Batch::JobDefinition

### Resource name

_No response_

### Description

Add an option to the CloudFormation definition of AWS Batch Job Definitions that will prevent updates which result in a new revision from deregistering the previous revision. At a minimum a simple boolean, conceptually something like `LeaveOldRevisionsActive`, would work. That puts the onus on clients to handle cleaning up older revisions though. Ideally it would include a count of the number of prior revisions to leave active, which would allow revisions to naturally be deregistered and eventually cleaned up without client involvement.

### Other Details

We adhere to a strict rule of immutable deploys, which means a given version of a deployed service always launches Batch jobs using a specific Job Definition revision. When we deploy a new version of a service there is a window of time between when the CloudFormation stack is updated and the new service code is active (and the old service code inactive) where launching jobs will fail because the CloudFormation update has deregistered the job definition revision that the old service code is reliant upon.

Start with the AWS::Batch::JobDefinition resource and the CloudFormation update behavior described in the issue. Define how an option or revision count should preserve prior revisions during immutable deployments, and consider the cleanup behavior that should make the change complete.

Written by the indexing model from the issue text.