Remove the ecs.yml section

[alaudazzi]

As ECS fields no longer need to be specified as part of an integration, this PR removes the ecs.yml section as requested in #3968.

[github-actions]

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[mergify]

This pull request does not have a backport label. Could you fix it @alaudazzi? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-/d./d is the label to automatically backport to the /d./d branch. /d is the digit
  NOTE: backport-skip has been added to this pull request.

[flash1293]

@ishleenk17 should there be changes to base.yml and agent.yml as well? I know we sometimes define values for constant keywords, those should stay, but maybe we can omit something else?

[ishleenk17]

@ishleenk17 should there be changes to base.yml and agent.yml as well? I know we sometimes define values for constant keywords, those should stay, but maybe we can omit something else?

Yes, the plan is to remove the ecs fields from these files. But, need to see how we can specify that in the documentation

[alaudazzi]

@ishleenk17

Yes, the plan is to remove the ecs fields from these files. But, need to see how we can specify that in the documentation

Is there any additional update expected on this page https://www.elastic.co/guide/en/integrations-developer/current/add-a-mapping.html#_agent_yml? Otherwise, we can handle further doc updates in separate PRs.

[alaudazzi]

@ishleenk17
A gentle reminder on this point.

[ishleenk17]

@ishleenk17 A gentle reminder on this point.

Lets handle the agent.yml and base-fields.yml in future PR's.
we are good to go on this one.