Add DISCLAIMER in Helm chart, fix LICENSE and NOTICE regarding code coming from Project Nessie in Helm chart (apache#1632)

Author: jbonofre

helm/polaris/DISCLAIMER

@@ -0,0 +1,10 @@
+Apache Polaris (incubating) is an effort undergoing incubation at The Apache
+Software Foundation (ASF), sponsored by the Apache Incubator PMC.
+
+Incubation is required of all newly accepted projects until a further review
+indicates that the infrastructure, communications, and decision making process
+have stabilized in a manner consistent with other successful ASF projects.
+
+While incubation status is not necessarily a reflection of the completeness
+or stability of the code, it does indicate that the project has yet to be
+fully endorsed by the ASF.

helm/polaris/LICENSE

@@ -199,3 +199,19 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
+
+--------------------------------------------------------------------------------
+
+This product includes code from Project Nessie.
+
+* helm/polaris/tests/logging_storage_test.yaml
+* helm/polaris/tests/quantity_test.yaml
+* helm/polaris/tests/service_monitor_test.yaml
+* helm/polaris/templates/_helpers.tpl
+* helm/polaris/templates/serviceaccount.yaml
+* helm/polaris/templates/servicemonitor.yaml
+* helm/polaris/templates/storage.yaml
+
+Copyright: Copyright 2015-2025 Dremio Corporation
+Home page: https://projectnessie.org/
+License: https://www.apache.org/licenses/LICENSE-2.0

helm/polaris/NOTICE

@@ -1,5 +1,13 @@
 Apache Polaris (incubating)
-Copyright 2024 The Apache Software Foundation
+Copyright 2025 The Apache Software Foundation
 
 This product includes software developed at
-The Apache Software Foundation (/).
+The Apache Software Foundation (http://www.apache.org/).
+
+--------------------------------------------------------------------------------
+
+This project includes code from Project Nessie, developed at Dremio,
+with the following copyright notice:
+
+| Nessie
+| Copyright 2015-2025 Dremio Corporation