tracking: Release Notes for SDP 26.3.0 (#828)

* docs: Add skeleton 26.3.0 release notes

* chore: Add summary of breaking changes section to release notes template

* docs: Add supported Kubernetes and OpenShift versions

* docs: Add MaxUnavailableStatefulSet known issue for K8s 1.35

* docs: Add product versions section

* docs: Add and simplify upgrade section

* docs: Add new miscellaneous platform features

* docs: Add new Airflow features

* docs: Add new Hive features

* docs: Add new Kafka features

* docs: Add new Spark features

* docs: Add new OPA features

* docs: Add new OpenSearch features

* docs: Add new listener-operator features

* docs: Add new secret-operator features

* docs: Add miscellaneous platform improvements

* docs: Add Airflow improvements

* docs: Add HBase improvements

* docs: Add Kafka improvements

* docs: Add NiFi improvements

* docs: Add Spark improvements

* docs: Add OPA improvements

* docs: Add Trino improvements

* docs: Add platform fixes

* docs: Add Airflow fixes

* docs: Add HBase fixes

* docs: Add NiFi fixes

* docs: Add Spark fixes

* docs: Add ZooKeeper fixes

* docs: Add OpenSearch fixes

* docs: Add Trino fixes

* docs: Add commons-operator fixes

* docs: Add Airflow removals

* docs: Add secret-operator removals

* docs: Add known issue for Kafka

* docs: Use correct heading in 25.11 release notes

* docs: Add vulnerability stats

* docs: Move HBase change, add Druid fix

* docs: Add HDFS restarter exception

* docs: Add missing changes

* docs: Improve various entries

* docs: Add summary of breaking changes

* chore: Fix indentation

* docs: Add release highlights

* chore: Add missing "a"

* docs: Add OpenSearch upgrade guide to admonition

* docs: Add graceful shutdown section

* docs: Add various small tweaks

* chore: Apply suggestions

Co-authored-by: Lars Francke <lars.francke@stackable.tech>

* chore: Adjust casing of "Breaking" item

* docs: Add missing link to OpenSearch PR

* chore: Use correct xref for NiFi usage guide

* chore: Move Kafka entry to "new features" section

* chore: Apply suggestions

Co-authored-by: Nick <10092581+NickLarsenNZ@users.noreply.github.com>
Co-authored-by: Malte Sander <malte.sander.it@gmail.com>

* chore: Improve Kafka KRaft migration link label

* docs: Add link to Airflow troubleshooting page

* docs: Improve NiFi OPA authorization improvement section

* docs: Add link to Spark pod placement page

* chore: Move Superset AUTH_OID removal

* docs: Improve secret-operator non-PV removal

* docs: Add known Druid 35+36 OIDC issue

* chore: Apply more suggestions

Co-authored-by: Lars Francke <lars.francke@stackable.tech>

* chore: Re-order objectOverrides entry

* chore: Apply suggestion

* docs: Mention default OPA package name for NiFi

* docs: Refine AUTH_OID removal entries

* docs: Refine OpenSearch security plugin entry

* chore: Various small finalizing tweaks

---------

Co-authored-by: Lars Francke <lars.francke@stackable.tech>
Co-authored-by: Nick <10092581+NickLarsenNZ@users.noreply.github.com>
Co-authored-by: Malte Sander <malte.sander.it@gmail.com>

Author: 4 people

modules/ROOT/pages/release-notes.adoc

@@ -7,6 +7,8 @@ The Stackable Data Platform consists of multiple operators that work together.
 Periodically a platform release is made, including all components of the platform at a specific version.
 
 // WARNING: Please keep the empty newlines, otherwise headings are broken.
+include::partial$release-notes/release-26.3.adoc[]
+
 include::partial$release-notes/release-25.11.adoc[]
 
 include::partial$release-notes/release-25.7.adoc[]

modules/ROOT/partials/release-notes/release-25.11.adoc

@@ -773,7 +773,7 @@ These Kubernetes versions are no longer supported:
 
 * `1.30`
 
-==== OpenShift
+===== OpenShift
 
 This release is available in the RedHat Certified Operator Catalog for the following OpenShift versions: