[SPARK-51382] Add submit-spark-connect-server.sh example

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to add submit-spark-connect-server.sh example to run SparkConnectServer on Spark Standalone Cluster.

Note that there are other ways to launch SparkConnectServer and this only aims to focus on Spark Standalone case.

Why are the changes needed?

1. Install Nightly Spark Kubernetes Operator and run a Spark cluster.

$ helm install spark-kubernetes-operator \
https://nightlies.apache.org/spark/charts/spark-kubernetes-operator-0.1.0-SNAPSHOT.tgz
NAME: spark-kubernetes-operator
LAST DEPLOYED: Mon Mar  3 20:55:41 2025
NAMESPACE: default
STATUS: deployed
REVISION: 1

$ kubectl apply -f prod-cluster-with-three-workers.yaml
sparkcluster.spark.apache.org/prod created

2. Setup port-forwarding.

$ kubectl port-forward svc/prod-master-svc 6066:6066

$ kubectl port-forward svc/prod-master-svc 6066:6066

3. Submit SparkConnectServer.

$ ./submit-spark-connect-server.sh
{
  "action" : "CreateSubmissionResponse",
  "message" : "Driver successfully submitted as driver-20250304045839-0000",
  "serverSparkVersion" : "4.0.0-preview2",
  "submissionId" : "driver-20250304045839-0000",
  "success" : true
}%

Does this PR introduce any user-facing change?

No. This is a newly added example.

How was this patch tested?

Manually follow the procedure.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

Thank you, @viirya .

[dongjoon-hyun]

Merged to main.