Create catalog-info file

[elastic-backstage-prod]

If you already have a ./catalog-info.yaml file defined in your repository, you probably want to close this PR.

If not - this PR provides you with the scaffolding for one. The catalog-info.yaml file is where you can define your infrastructure needs (such as Buildkite pipelines) in the form of Real Resource Entities.


If you already have a Buildkite pipeline defined in the elastic/ci repository, you can copy its definition in this catalog-info.yaml file (see instructions).

Once the pipeline definition is ingested into Backstage, Terrazzo will emit a warning about a duplicate definition with a warning similar to:
🙈 Ignoring remote manifest in favour of local one: buildkite.elastic.dev/v1=>Pipeline=> your-pipeline

At this point, it is safe for you to delete the Pipeline definition from the elastic/ci repository.

[cla-checker-service]

❌ Author of the following commits did not sign a Contributor Agreement:
a240ec0

Please, read and sign the above mentioned agreement if you want to contribute to this project