Docs: add airflow, HDFS and superset supported products (#699)

* add airflow and superset to supported products

* order alphabetically

* add hdfs

* Update docs/modules/opa/pages/index.adoc

Co-authored-by: Lars Francke <jujutsu@lars-francke.de>

---------

Co-authored-by: Lars Francke <jujutsu@lars-francke.de>

Author: maltesander

docs/modules/opa/pages/index.adoc

@@ -48,8 +48,11 @@ OPA and the Stackable operator for OPA do not have any dependencies.
 
 Currently the following products on the Stackable Data Platform support policy decisions with OPA:
 
+* xref:airflow:usage-guide/security.adoc#_open_policy_agent[Apache Airflow]
 * xref:druid:usage-guide/security.adoc#_authorization_with_open_policy_agent_opa[Apache Druid]
+* xref:hdfs:usage-guide/security.adoc#_authorization[Apache Hadoop HDFS]
 * xref:kafka:usage-guide/security.adoc#_authorization[Apache Kafka]
+* xref:superset:usage-guide/security.adoc#_opa_role_mapping[Apache Superset]
 * xref:trino:usage-guide/security.adoc#_authorization[Trino]
 
 == Supported versions