MGB Patients/Primary Payer Feature Release Branch

This is the combination of two feature workstreams into a singe release merge.

The goal of this change is to provide a way of easily identifying patients that we consider to be our primary care patients in a more exhaustive way than the existing PatientPartnersPatients view. In addition, this change adds a "Primary Payer" view, so that we can easily identify a patient's preferred coverage.

This feature is based on existing work by Jill and Ellyn that was previously encapsulated in a SAS program. A number of adjustments were made to the code to make it more robust. A number of bugs were identified and resolved in the process. These changes are documented in both the code and commit messages. Please review them thoroughly. The output from these views is not a mirror of the output from the existing SAS program.

These changes have been reviewed by members of the enterprise analytics department, and their feedback was incorporated into many of the business decisions found in the code.

Additional reviews would be greatly appreciated. Please leave any feedback by 2/12/2021.

Once merged, PatientMGBPatients is the source of truth for the MGB primary care population. To aid in transition away from PatientPartnersPatients, an announcement will be made of the latter view's deprecation. For an interim period we will source PatientPartnersPatients from PatientMGBPatients, so that projects using the former will receive the most up-to-date patient lists.