Automate adding patient identifier types to OpenMRS

[witash]

The CHT OpenMRS mediator needs to send identifiers from CHT to openmrs.
To do this, it uses two new identifier types; CHT Patient ID and CHT Document ID.
Currently, these have to be added manually, or via a REST call (as in e2e tests)
Ideally, this would be automatic, when the OpenMRS mediator first starts.
One complication is that there is no way to do this with the FHIR Api, so it would need to have another channel for the REST API