Write parquet to STDOUT

https://github.com/Parquet/parquet-mr/blob/master/parquet-hadoop/src/main/java/parquet/hadoop/ParquetWriter.java

I would like to write the parquet to stdout but there is no option to let me do this. Also the file must not already exist, or I' ll get Exception.

Thanks

**Reporter**: [Federico Ponzi](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=federicoponzi)

_{**Note**: *This issue was originally created as [PARQUET-570](https://issues.apache.org/jira/browse/PARQUET-570). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start with parquet-hadoop/src/main/java/parquet/hadoop/ParquetWriter.java and trace how output paths are opened and how existing-file checks are applied. Determine where a stdout destination could be supported without breaking normal file output. Done means parquet data can be written to stdout through a documented option, with coverage for the new behavior.

Written by the indexing model from the issue text.