[SPARK-29070][CORE] Make SparkLauncher log full spark-submit command line

Log the full spark-submit command in SparkSubmit#launchApplication

Adding .python-version (pyenv file) to RAT exclusion list

### What changes were proposed in this pull request?

Original motivation [here](http://apache-spark-user-list.1001560.n3.nabble.com/Is-it-possible-to-obtain-the-full-command-to-be-invoked-by-SparkLauncher-td35144.html), expanded in the [Jira](https://issues.apache.org/jira/browse/SPARK-29070)..  In essence, we want to be able to log the full `spark-submit` command being constructed by `SparkLauncher`

### Why are the changes needed?

Currently, it is not possible to directly obtain this information from the `SparkLauncher` instance, which makes debugging and customer support more difficult.

### Does this PR introduce any user-facing change?

No

### How was this patch tested?

`core` `sbt` tests were executed.  The `SparkLauncherSuite` (where I added assertions to an existing test) was also checked.  Within that, `testSparkLauncherGetError` is failing, but that appears not to have been caused by this change (failing for me even on the parent commit of c18f849).

Closes #25777 from jeff303/SPARK-29070.

Authored-by: Jeff Evans <[email protected]>
Signed-off-by: Marcelo Vanzin <[email protected]>

Author: jeff303

launcher/src/main/java/org/apache/spark/launcher/SparkLauncher.java

@@ -26,8 +26,11 @@
 import java.util.Map;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import static org.apache.spark.launcher.CommandBuilderUtils.*;
+import static org.apache.spark.launcher.CommandBuilderUtils.join;
 
 /**
  * Launcher for Spark applications.
@@ -38,6 +41,8 @@
  */
 public class SparkLauncher extends AbstractLauncher<SparkLauncher> {
 
+  private static final Logger LOG = Logger.getLogger(SparkLauncher.class.getName());
+
   /** The Spark master. */
   public static final String SPARK_MASTER = "spark.master";
 
@@ -363,6 +368,9 @@ public SparkAppHandle startApplication(SparkAppHandle.Listener... listeners) thr
 
     String loggerName = getLoggerName();
     ProcessBuilder pb = createBuilder();
+    if (LOG.isLoggable(Level.FINE)) {
+      LOG.fine(String.format("Launching Spark application:%n%s", join(" ", pb.command())));
+    }
 
     boolean outputToLog = outputStream == null;
     boolean errorToLog = !redirectErrorStream && errorStream == null;