chore(25.3.0): Add TLS certificate configurable lifetime feature

Author: NickLarsenNZ

modules/ROOT/partials/release-notes/release-25.3.adoc

@@ -14,6 +14,8 @@ Security::
 * Additional trust roots can be specified in an `autoTls` SecretClass. See xref:secret-operator:secretclass.adoc[Documentation].
 * The Stackable Secret Operator's `experimentalCertManager` backend now supports specifying custom key lengths.
   The `autoTls` backend has supported this since 24.11.
+* Users can now configure the lifetime of self-signed certificates directly in the product's custom resources which influences the frequency of pod restarts.
+  Details can be found at xref:concepts:operations/temporary_credentials_lifetime.adoc[].
 
 ==== Platform improvements