change databricks ma hashing from workaround to listagg function sinc…

[jstendel]

Changed Databricks ma hashing from workaround to listagg() function since support for function was added in Databricks Runtime version 16.4

Description

Please include a summary of the changes and the related issue and context.

Fixes #183

Type of change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
  => removes current workaround

How Has This Been Tested?

Checked result of ma Hashdiffs before and after change inside Databricks, results are the same

Checklist:

• I have performed a self-review of my code
• I have made corresponding changes to the documentation or included information that needs updates (e.g. in the Wiki)

[tkirschke]

@tkiehn can this be converted to ready-for-review?