## What changes were proposed in this pull request?

This PR adds ML examples for the FeatureHasher transform in Scala, Java, Python.

## How was this patch tested?

Manually ran examples and verified that output is consistent for different APIs

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #19024 from BryanCutler/ml-examples-FeatureHasher-SPARK-21810.