feat: split metadata into smal pieces

Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: gtema <artem.goncharov@gmail.com>
Co-committed-by: gtema <artem.goncharov@gmail.com>

otc_metadata/data/documents/ecs-api-ref.yaml

@@ -0,0 +1,9 @@
+---
+hc_location: api/ecs
+html_location: docs/ecs/api-ref
+link: /elastic-cloud-server/api-ref/
+pdf_name: ecs-api-ref
+rst_location: api-ref/source
+service_type: ecs
+title: API Reference
+type: api-ref