[ECS] [request]: Add EventBridge events for Task Definitions

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

Generate Events via EventBridge for Registration and Deregistration of new/existing Task Definitions

**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?**

There is currently no notification/event that is generated in the case that a New Task Defintion is registered.

This will allow CI/CD to be triggered for new revisions.

This will also allow for event driven architectures to be triggered in case there is a registration or deregistration of a Task Definition.

**Are you currently working around this issue?**
No, there is currently no way of receiving notifications or events.

**Additional context**
n/a
Anything else we should know?
n/a

No files, tests, or implementation entry points are named in the issue. Start by reviewing the requested ECS and EventBridge behavior; done would mean events are generated for registration and deregistration of task definitions.

Written by the indexing model from the issue text.