Add support for StringSplit

[andygrove]

What is the problem the feature request solves?

https://spark.apache.org/docs/latest/api/python/reference/pyspark.sql/api/pyspark.sql.functions.split.html

Describe the potential solution

Please refer to the contributor guide:

Adding a New Expression - Comet Contributor Guide

This guide walks through the process of adding expression support to Comet.

Additional context

No response

[manuzhang]

I'd like to work on this task.

[rishabhjain1712]

@rishabhjain1712