adding api-usage metadata

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

otc_metadata/data/documents/apiu-guidelines.yaml

@@ -0,0 +1,9 @@
+---
+hc_location: api-usage/guidelines
+html_location: docs/apiu/guidelines
+link: /api-usage/guidelines/
+pdf_name: apiu-guidelines
+rst_location: doc/tool/source
+service_type: apiu
+title: API Usage Guidelines
+type: guidelines

otc_metadata/data/services/apiu.yaml

@@ -0,0 +1,16 @@
+---
+environment: public
+repositories:
+- environment: internal
+  repo: docs/api-usage
+  type: gitea
+- environment: public
+  repo: opentelekomcloud-docs/api-usage
+  type: github
+service_category: other
+service_title: API Usage
+service_type: apiu
+service_uri: api-usage
+teams:
+- name: eco
+  permission: write