Support ecs-cli

[neowulf]

There should be a way to configure ecs-cli in such a way that this stack can be managed via ecs-cli if the need arises. A command such as follows would be sufficient to configure ecs-cli:

ecs-cli configure --region us-west-2 --profile sandbox --cluster ${STACK_NAME} --compose-project-name-prefix "${STACK_NAME}-" --compose-service-name-prefix "${STACK_NAME}-" --cfn-stack-name-prefix "${STACK_NAME}-"