ECS [request]: Consistent event messages

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**Tell us about your request**
The event messages should be consistent and always contain the task id.

For example "service 'foo' has started 1 tasks: task " contains the task id, but the follow up event "registered 1 targets in targetgroupy 'xy'" doesn't contain the task id.

There might be more events where the task id would be useful.

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

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
All task-related events should contain the task ids. This makes it easier to get an exact timeline in case of troubleshooting. Maybe it would be even better to have a task-filter on all these events as well (maybe similar to #103 )

**Are you currently working around this issue?**
Guessing which event is related.

No implementation files or tests are identified in this roadmap issue. Start by reviewing the ECS/Fargate event behavior described here and the related task-filter issue #103. Done would require a decided scope for task-related events, consistent task IDs, and possibly task filtering, but the request does not define which events are included.

Written by the indexing model from the issue text.