Try to use jgo for classpath instead of shaded fat jar

Needs
 - mvn on classpath
 - jgo from [resolve-only](scijava/jgo#37) pull request (Python >= 3.7)

Currently fails with:
```
Unable to convert into Paintera dataset: Job aborted due to stage failure: Task 1 in stage 0.0 failed 4 times, most recent failure: Lost task 1.3 in stage 0.0 (TID 736, 10.36.110.15, executor 69): java.lang.NoSuchMethodError: org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream.<init>(Ljava/io/Ou
        at org.janelia.saalfeldlab.n5.GzipCompression.getOutputStream(GzipCompression.java:89)
        at org.janelia.saalfeldlab.n5.DefaultBlockWriter.write(DefaultBlockWriter.java:49)
        at org.janelia.saalfeldlab.n5.DefaultBlockWriter.writeBlock(DefaultBlockWriter.java:83)
        at org.janelia.saalfeldlab.n5.N5FSWriter.writeBlock(N5FSWriter.java:133)
        at org.janelia.saalfeldlab.n5.imglib2.N5LabelMultisets.saveLabelMultisetBlock(N5LabelMultisets.java:308)
        at org.janelia.saalfeldlab.n5.imglib2.N5LabelMultisets.saveLabelMultisetBlock(N5LabelMultisets.java:337)
        at org.janelia.saalfeldlab.label.spark.convert.ConvertToLabelMultisetType.lambda$convertToLabelMultisetType$dce05d2$1(ConvertToLabelMultisetType.java:226)
        at org.apache.spark.api.java.JavaPairRDD$$anonfun$toScalaFunction$1.apply(JavaPairRDD.scala:1040)
        at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
        at scala.collection.Iterator$class.foreach(Iterator.scala:893)
        at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
        at scala.collection.TraversableOnce$class.reduceLeft(TraversableOnce.scala:185)
        at scala.collection.AbstractIterator.reduceLeft(Iterator.scala:1336)
        at org.apache.spark.rdd.RDD$$anonfun$reduce$1$$anonfun$14.apply(RDD.scala:1015)
        at org.apache.spark.rdd.RDD$$anonfun$reduce$1$$anonfun$14.apply(RDD.scala:1013)
        at org.apache.spark.SparkContext$$anonfun$33.apply(SparkContext.scala:2130)
        at org.apache.spark.SparkContext$$anonfun$33.apply(SparkContext.scala:2130)
        at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
        at org.apache.spark.scheduler.Task.run(Task.scala:109)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:345)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
```

Probably dependency issue between spark and N5 (or other libraries) that is not an issue with shaded fat jar.

flintstone-jgo.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+if [ "$#" -lt "3" ]; then
+    echo -e "Not enough arguments!" 1>&2
+    exit 1
+fi
+
+CONTAINING_DIRECTORY="$( dirname "${BASH_SOURCE[0]}" )"
+SPARK_JANELIA="${SPARK_JANELIA:-${CONTAINING_DIRECTORY}/spark-janelia/spark-janelia}"
+# MVN="${MVN:-/misc/local/maven-3.2.2/bin/mvn}"
+
+RUNTIME="${RUNTIME:-8:00}"
+SPARK_VERSION="${SPARK_VERSION:-2.3.1}"
+TERMINATE="${TERMINATE:-1}"
+MIN_WORKERS="${MIN_WORKERS:-1}"
+
+N_EXECUTORS_PER_NODE="${N_EXECUTORS_PER_NODE:-6}"
+N_CORES_PER_EXECUTOR="${N_CORES_PER_EXECUTOR:-5}"
+MEMORY_PER_NODE="${MEMORY_PER_NODE:-300}"
+SPARK_OPTIONS="${SPARK_OPTIONS:-}"
+
+N_DRIVER_THREADS="${N_DRIVER_THREADS:-16}"
+
+N_NODES=$1;           shift
+COORDINATE="$1";      shift
+CLASS=$1;             shift
+ARGV="$@"
+
+ARTIFACT="$(echo $COORDINATE | tr ':' '\n' | head -n2 | tail -n1)"
+WORKSPACE="$(jgo --repository scijava.public=https://maven.scijava.org/content/groups/public --resolve-only $COORDINATE)"
+MAIN_JAR="$(ls ${WORKSPACE}/*jar -1 | grep -E "${ARTIFACT}-[0-9]+")"
+ALL_JARS="$(ls ${WORKSPACE}/*jar -1 | tr '\n' ',' | sed 's/,$//')"
+
+# echo "$MEMORY_PER_NODE / $N_EXECUTORS_PER_NODE"
+# echo "$N_NODES * $N_EXECUTORS_PER_NODE"
+export MEMORY_PER_EXECUTOR="$(($MEMORY_PER_NODE / $N_EXECUTORS_PER_NODE))"
+export N_EXECUTORS="$(($N_NODES * $N_EXECUTORS_PER_NODE))"
+export PARALLELISM="$(($N_EXECUTORS * $N_CORES_PER_EXECUTOR * 3))"
+
+SUBMIT_ARGS="${SUBMIT_ARGS} --verbose"
+SUBMIT_ARGS="${SUBMIT_ARGS} --conf spark.default.parallelism=$PARALLELISM"
+SUBMIT_ARGS="${SUBMIT_ARGS} --conf spark.executor.instances=$N_EXECUTORS_PER_NODE"
+SUBMIT_ARGS="${SUBMIT_ARGS} --conf spark.executor.cores=$N_CORES_PER_EXECUTOR"
+SUBMIT_ARGS="${SUBMIT_ARGS} --conf spark.executor.memory=${MEMORY_PER_EXECUTOR}g"
+SUBMIT_ARGS="${SUBMIT_ARGS} ${SPARK_OPTIONS}"
+SUBMIT_ARGS="${SUBMIT_ARGS} --jars $ALL_JARS"
+SUBMIT_ARGS="${SUBMIT_ARGS} --class $CLASS"
+SUBMIT_ARGS="${SUBMIT_ARGS} ${MAIN_JAR}"
+SUBMIT_ARGS="${SUBMIT_ARGS} ${ARGV}"
+
+LOG_FILE="${HOME}/.sparklogs/${CLASS}.o%J"
+
+"${SPARK_JANELIA}" \
+    --nnodes="${N_NODES}" \
+    --no_check \
+    --driveronspark \
+    --silentlaunch \
+    --minworkers="${MIN_WORKERS}" \
+    --hard_runtime=${RUNTIME} \
+    --submitargs="${SUBMIT_ARGS}" \
+    --driveroutfile=${LOG_FILE} \
+    lsd