aws ecs deploy should incorporate time to shift traffic for wait time calculation

**Is your feature request related to a problem? Please describe.**

The `aws ecs deploy` command calculate the expected duration for a deployment based on the configured wait and termination time only, but in case of a canary deployment additional time is required to shift the traffic to the new version step by step. This leads to failed execution of the command, because the command gives up way to early - while the deployment is still not finished yet.

**Describe the solution you'd like**

Take the values of the traffic rerouting in consideration if the expected duration of the deployment is calculated.

**Describe alternatives you've considered**

Allow to override the expect deployment duration via some command line switch.

**Additional context**

https://aws.amazon.com/about-aws/whats-new/2020/02/amazon-elastic-container-service-support-canary-deployments/