[ECS] [request]: Support awsvpc networking for CentOS running a ecs-agent docker container

**Tell us about your request**
What do you want us to build?
Support awsvpc networking for CentOS which has ecs-agent docker container. CentOS does not include a ecs-init package which provides the ability to run a task with awsvpc networking.

Similar issues have been reported for non-Amazon Linux AMI's https://github.com/aws/amazon-ecs-agent/issues/1083, https://github.com/aws/amazon-ecs-init/issues/150

**Which service(s) is this request for?**
ECS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.
Organizations required CIS hardened images to be run which can be non-amazon linux for ECS tasks and any task which requires AWSVPC networking will be affected by this.

**Are you currently working around this issue?**
How are you currently solving this problem?
I am trying to solve the problem by the workaround mentioned here: https://github.com/aws/amazon-ecs-agent/issues/1083 and it works. It would be great if CentOS can natively support that.

**Additional context**
Anything else we should know?
-None-

**Attachments**
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Start by reading the workaround referenced in amazon-ecs-agent issue #1083 and the related amazon-ecs-init issue #150 to understand the current approach for non-Amazon Linux images. Compare those discussions with the CentOS ecs-agent Docker-container setup described here. Done means CentOS natively supports ECS tasks requiring awsvpc networking without relying on that workaround.

Written by the indexing model from the issue text.