[SPARK-7861][ML] PySpark OneVsRest

## What changes were proposed in this pull request?

https://issues.apache.org/jira/browse/SPARK-7861

Add PySpark OneVsRest. I implement it with Python since it's a meta-pipeline.

## How was this patch tested?

Test with doctest.

Author: Xusen Yin <yinxusen@gmail.com>

Closes #12124 from yinxusen/SPARK-14306-7861.