Add pdf environment switch

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/geminidb-api-ref.yaml

@@ -3,6 +3,7 @@ hc_location: api/nosql
 html_location: docs/geminidb/api-ref
 link: /geminidb/api-ref/
 pdf_enabled: true
+pdf_environment: internal
 rst_location: api-ref/source
 service_type: geminidb
 title: API Reference