describe metadata overview

Reviewed-by: Gode, Sebastian <sebastian.gode@t-systems.com>
Co-authored-by: tischrei <tino.schreiber@t-systems.com>
Co-committed-by: tischrei <tino.schreiber@t-systems.com>

otc_metadata/data/documents/README.md

@@ -0,0 +1,69 @@
+# 📁 documents/
+
+This folder contains metadata about documentation files per service, such as user guides or API references. Each file describes a single document variant for a specific cloud environment.
+
+## 🔧 Example: `ecs-umn.yaml`
+
+```yaml
+---
+hc_location: usermanual/ecs
+html_location: docs/ecs/umn
+link: /elastic-cloud-server/umn/
+rst_location: umn/source
+service_type: ecs
+title: User Guide
+type: umn
+cloud_environments:
+  - name: eu_de
+    visibility: public
+    pdf_visibility: public
+    pdf_enabled: true
+  - name: swiss
+    visibility: public
+    pdf_visibility: public
+    pdf_enabled: true
+```
+
+## 🔧 Example: `ecs-api-ref.yaml`
+
+```yaml
+---
+hc_location: api/ecs
+html_location: docs/ecs/api-ref
+link: /elastic-cloud-server/api-ref/
+rst_location: api-ref/source
+service_type: ecs
+title: API Reference
+type: api-ref
+cloud_environments:
+  - name: eu_de
+    visibility: public
+    pdf_visibility: public
+    pdf_enabled: true
+  - name: swiss
+    visibility: public
+    pdf_visibility: public
+    pdf_enabled: true
+```
+
+## Parameter Reference
+
+| Field                | Type   | Description                                              |
+| -------------------- | ------ | -------------------------------------------------------- |
+| `hc_location`        | string | Path used in the Horizon Console.                        |
+| `html_location`      | string | Location of the built HTML output.                       |
+| `link`               | string | Target URL segment for this document.                    |
+| `rst_location`       | string | Source folder for `.rst` input.                          |
+| `service_type`       | string | Related service identifier (matches `services/`).        |
+| `title`              | string | Display name of the document.                            |
+| `type`               | string | Document type (e.g., `umn`, `api-ref`, etc.).            |
+| `cloud_environments` | list   | Region-specific metadata like visibility or PDF support. |
+
+### `cloud_environments` Options:
+
+| Field            | Type    | Allowed Values                 | Description                        |
+| ---------------- | ------- | ------------------------------ | ---------------------------------- |
+| `name`           | string  | e.g., `eu_de`, `swiss`         | Name of the cloud region.          |
+| `visibility`     | string  | `public`, `internal`, `hidden` | Document visibility level.         |
+| `pdf_visibility` | string  | `public`, `internal`, `hidden` | PDF visibility level               |
+| `pdf_enabled`    | boolean | `true`, `false`                | Enable PDF export                  |