allow specification of patient names when generating ehr data

When generating ehr data (synthetic or using our group's data table) currently the patient names are generated randomly each time. If one starts with some images in an orthanc server and wants to demo this application, then this random name generation will cause a mismatch between the names in the ehr system and then names in the dicom metadata. This is kind of weird so it should be possible to somehow specify the desired patient names just like [we can choose to specify patient IDs](https://github.com/KitwareMedical/lungair-web-application/blob/a4d6352fd6feed21f0355d44848a323b30bb8930/lungair/fhir-sandbox-config/lungair_data_source.json#L5).