Simplify code and eager-load person. #3783
Changed EligibilityAdjudicator to be included on Participant and more. #3783

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1. Changed ::adjudicate_eligibility to only group participants by eligible or ineligible
2. Added ::disqualify method to remove participant(s) from the study
3. Added ::adjudicate_eligibility_and_disqualify_ineligible to do both of above