Refactor note clean up script

Part 5 of gitlab-org/gitlab-qa#639 (closed)

Refactors the stale note_clean_up script to automatically close out old test result issues that have too many notes. We had to pivot from it's original intention !74 (comment 567184289).

Notes: A new results issue will be automatically created and linked to the proper Test Case when running a pipeline that runs the results script. The closed issued will still be linked in the Test Case to preserve test history. This prevents memory issues and reduces manual intervention for SETs when results issues get too big.