Add Primary Key argument option

[OlivieFranklova]

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

spark-submit <spark-config> dataset-comparison.jar <other-options> --pk-columns Column1,Column2,ColumnX

Original author: @Zejnilovic