[ECS] [feature request]: Authenticate image pulls from ECR Public in ECS/EC2 and Fargate

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**Tell us about your request**
What do you want us to build?

Authenticated image pulls from ECR Public in ECS

**Which service(s) is this request for?**
This could be Fargate, ECS, EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**

ECR public currently allows for 10 image pulls per second from within AWS (see [ecr public quotas page](https://docs.aws.amazon.com/AmazonECR/latest/public/public-service-quotas.html)), but this quota limit is not adjustable.

Authenticated image pulls also allow 10 per second by default, but the limit is adjustable.

So customers running workloads that rely on ECR public are currently not able to easily scale beyond 10 image pulls per second.

**Are you currently working around this issue?**
How are you currently solving this problem?

Private registry auth might work, but is much less convenient than private ECR's builtin auth: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/private-auth.html

Alternatively, mirroring public ECR images in private ECR.

Start with the ECR Public service quotas page and the ECS private registry authentication documentation linked in the issue, then determine which ECS/EC2 and Fargate workflows need authenticated ECR Public pulls. Done means a defined and implemented way for those workloads to authenticate and scale beyond the unauthenticated pull limit.

Written by the indexing model from the issue text.