ECS CodeDeploy and Preserve Task Definition Configuration

Adding this issue to track and plan for the following community contribution. !15 (closed)

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

When creating a new revision of the task definition, it makes sure that attributes that were not taken into consideration before (eg. memory, cpu...) are not forgotten.

It introduces a new aws command:aws deploy create-deploymentwhich Deploys an application revision through the specified deployment group.