Add Primary Key argument option

# Description

Allow users to specify primary key or composite primary key columns for easier comparison between the two tables. This will allow us to compare rows that is known that are supposed to be the same.

# Feature
- add input argument for list of column names

# Example
```sh
spark-submit dataset-comparison.jar --pk-columns Column1,Column2,ColumnX
```

> Original author: @Zejnilovic