[ECS] [request]: ecs-agent support elastic-logging-plugin

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**Tell us about your request**
Elastic has published a docker plugin to support logging to an elastic stack, it would be helpful if this was supported via the ecs-agent.

**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?**
My company requires logs to be sent to elastic for our applications which are moving to ECS. It would greatly simplify our logging setup if we could easily use the elastic logging plugin.
(https://www.elastic.co/guide/en/beats/loggingplugin/current/index.html)

**Are you currently working around this issue?**
without this support we're looking at using a lambda to ship logs to elastic or I have seen some posts about using the fluentd driver.

Thanks

No repository files, tests, or entry points are named. Start by reviewing the linked Elastic logging plugin documentation and ECS logging capabilities; done would mean documented ECS agent support for using the plugin to send application logs to Elastic.

Written by the indexing model from the issue text.