MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes #1328 (close requested by 'pwendell')
Closes #2314 (close requested by 'pwendell')
Closes #997 (close requested by 'pwendell')
Closes #550 (close requested by 'pwendell')
Closes #1506 (close requested by 'pwendell')
Closes #2423 (close requested by 'mengxr')
Closes #554 (close requested by 'joshrosen')
[SPARK-3595] Respect configured OutputCommitters when calling saveAsHadoopFile

Addresses the issue in https://issues.apache.org/jira/browse/SPARK-3595, namely saveAsHadoopFile hardcoding the OutputCommitter.  This is not ideal when running Spark jobs that write to S3, especially when running them from an EMR cluster where the default OutputCommitter is a DirectOutputCommitter.

Author: Ian Hummel <ian@themodernlife.net>

Closes #2450 from themodernlife/spark-3595 and squashes the following commits:

f37a0e5 [Ian Hummel] Update based on comments from pwendell
a11d9f3 [Ian Hummel] Fix formatting
4359664 [Ian Hummel] Add an example showing usage
8b6be94 [Ian Hummel] Add ability to specify OutputCommitter, espcially useful when writing to an S3 bucket from an EMR cluster
[Minor]ignore .idea_modules

ignore .idea_modules ,  ```sbt/sbt gen-idea``` generate this dir.

Author: wangfei <wangfei1@huawei.com>

Closes #2476 from scwf/patch-4 and squashes the following commits:

e6ab88a [wangfei] ignore .idea_modules
Merge branch 'master' of git://git.apache.org/spark into metrics-structure-improvement2
Modified CoarseGrainedMesosSchedulerBackend and MesosSchedulerBackend so that we can get Application ID

Modified MesosExecutorBackend to be able to get Application ID