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 c18f849d76).
Closes#25777 from jeff303/SPARK-29070.
Authored-by: Jeff Evans <jeffrey.wayne.evans@gmail.com>
Signed-off-by: Marcelo Vanzin <vanzin@cloudera.com>
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