Add task auto-scaling to services

[james-jory]

Add ECS task auto scaling policy to services to allow them to scale in/out based on CPU. The purpose of this task is to demonstrate how auto-scaling can be configured in the deployment of services to support changes in traffic and load (i.e. Flash sale).

This task would also add practical value to workshops such as the Experimentation workshops that add spikes in load against the recommendations and products services while simulating experiments. Auto-scaling should help improve performance of experiment simulations.