Add Data Quality Results Comparison Utility

[fdefalco]

Given two result files identify for the latest file the number of, and identifiers for:

• new issues that did not exist in the prior report
• resolved issues that existed in the prior report but not in the current report
• persisting issues that existed in the prior report and in the current report

[MelaniePhilofsky]

I have an additional feature suggestion for the comparison utility tool @fdefalco and @clairblacketer :)
It would be nice to see the trend of results over time. A 1% increase in the unmapped rate for a concept_id might not be significant enough to raise a red flag. But that 1% increase every time the DQD is run is quite significant when the DQD is run on a frequent basis (scheduled 2x/week in Colorado).

[MaximMoinat]

We have made in the past a 'compareDqdPlot': #252