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/README.md

@@ -0,0 +1,26 @@
+# 📁 data/
+
+This directory is the core of the metadata structure for Open Telekom Cloud Service Documentation. It contains structured definitions for services, their document types, categories, and repository configurations.
+
+## 📂 Folder Overview
+
+| Folder Name         | Description                                                                 |
+|---------------------|-----------------------------------------------------------------------------|
+| `services/`          | Contains metadata for each individual service, including its cloud regions and access teams. |
+| `documents/`         | Holds metadata about documentation types (e.g., user guides, API refs) for each service and cloud region. |
+| `service_categories/`| Lists available service categories used to group services (e.g., "Application", "Database"). |
+| `repositories/`      | Defines where the documentation source code is located (GitHub or Gitea) for each service per cloud environment. |
+
+## 📦 Usage
+
+These metadata files are used to:
+- Build documentation portals.
+- Generate links and visibility rules dynamically.
+- Control contributor access.
+- Connect documentation to source control repositories.
+
+Each subfolder contains its own `README.md` with detailed field references and options.
+
+## 📎 Example Structure
+
+![Folder Structure](./folder_structure.png)