Add support for ECS Fargate service auto scaling

[genadis]

We are using ECS FargateService, and would like the tasks to be auto-scalable. At the moment this cannot be easily achieved. Our only option now is to switch to ECS EC2Service and use the Autoscaling group.

AWS does support ECS Fargate service autoscaling (via CloudWatch alarms): https://aws.amazon.com/premiumsupport/knowledge-center/ecs-fargate-service-auto-scaling/

This can be configured via AWS Console, would be great to have this support in Crosswalk similar to createAutoScalingGroup.

Affected feature

ECS FargateService