Add CloudFormation template for adding a job def

[Lewis Fishgold]

The current workflow is for each develop to run the template to create an entirely new stack. This seemed like a good idea except that there is a limit on number of queues and compute environments https://docs.aws.amazon.com/batch/latest/userguide/service_limits.html, and the Batch console loads very slowly once you have more than a few of these (it seems to make a fetch for each queue and state combination).

It seems like a better workflow is to create the full stack once per account and then each developer will just create their own job def which reference the global job queue and compute environments.