Replace cause numbers with hashes in final JSON

[nicolassaw]

Problem
Cause numbers may be able to identify an individual if someone searches the cause number in the data and identifies the person. Accordingly, we can replace cause numbers with hashes to disguise the cause number while maintaining a consistent identifier.

Goal
Add code to the clean module that adds a hash of the cause number to the final json file. Remove the step that adds the cause number.

[nicolassaw]

This has been fully implemented in the cleaner module under PR #139.

Accordingly, this ticket can be closed.