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/gaussdb_mysql-api-ref.yaml

@@ -2,7 +2,8 @@
 hc_location: api/gaussdb
 html_location: docs/gaussdb_mysql/api-ref
 link: /gaussdb-mysql/api-ref/
-pdf_name: gaussdb_mysql-api-ref
+pdf_enabled: true
+pdf_environment: internal
 rst_location: api-ref/source
 service_type: gaussdb_mysql
 title: API Reference