setup spark standalone

[Tianhao-Gu]

(dev) tgu@cdm-spark-standalone (master)$docker exec -it spark-user \
    sh -c '
            /opt/bitnami/spark/bin/spark-submit \
                    --master $SPARK_MASTER_URL \
                    /opt/bitnami/spark/examples/src/main/python/pi.py 10 \
                    2>/dev/null
    '
Pi is roughly 3.136920

What's next:
    Try Docker Debug for seamless, persistent debugging tools in any container or image → docker debug spark-user
    Learn more at https://docs.docker.com/go/debug-cli/
(dev) tgu@cdm-spark-standalone (master)$

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[Tianhao-Gu]

code changes are all copied from cdm-jupyterhub repo.

[Tianhao-Gu]

closing PR, we will use old image from ghcr.io/kbase/cdm-jupyterhub for spark standalone mode.