Add Patient Program to Patient Identifier

*Talk Post *
https://talk.openmrs.org/t/patient-program-identifiers/35791

Detail
Patients during care in a given program such as Tuberculosis, Antenatal, etc.., require to be identified with identifiers that are associated with the program they are enrolled into.

The Current Implementation of patient identifiers does not link to a patient program except to a patient. This is not enough when it comes to Identifying a patient in a specific program.

There is a need to link that patient identifier to a patient program in order to have

1. Multiple identifiers per patient identifier type that is linked to a patient program
2. Enable linking of identifiers attached to an EpisodeOfCare (PatientProgram)

*Implementation approach. *

1. Add a patient program column, that is nullable to the patient identifier.