ECS CodeDeploy and Preserve Task Definition Configuration

Deploying to a service backed by ECS CodeDeploy controller fails with an error asking you to create a Code Deployment task instead This request fixes this by adding a separate command create-deployment to ecs to support this, currently the json is rather limited but it's easy to extend

This also refactors part of the previous register-task-definition code to source it from the original json to persist as much of the original task definition settings as possible.

Closes #10 (closed)