[ECS] [request]: HTTP Health check for ECS

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**Tell us about your request**
I would like to see support for a HTTP health check in ECS.

**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?**
Right now ECS supports container health check. A command defined in the task definition is executed inside the container to determine the health status.
Most containers for web apps implement this kind of health check by adding tools like curl or wget in the container for the healthcheck. While being easy to implement this approach results in containers with tools that are not really needed by the web app at runtime, bigger image size and larger attack surface.
Hence, I would like ECS to support a HTTP health check which is executed by ECS (not from within the container) to determine the health status.
This will remove the dependency on tools like curl or wget to be present inside the container.

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

**Additional context**
Anything else we should know?

**Attachments**
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