[ECS] [request]: Allow daemon scheduleing strategy, placement constraints for ECS-Anywhere

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**Tell us about your request**
I would like to enable daemon-type scheduling and placement constraints for services running on external instances through ECS-Anywhere

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

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
I have customers who have expressed a need to use external/on-prem resources to host their services, but also have business case need for the service to run as a daemon process. Currently, there seems to be no mechanism to do this, as this scheduling strategy is not supported for external services. Additionally, placement constraints are not part of the schema for external task definitions, which could be leveraged for a facsimile of this paradigm.

**Are you currently working around this issue?**
I am currently unaware of any known workaround for this issue

**Additional context**

**Attachments**