Should be able to configure fields used to create subjects from experiment data

If a DICOM session is received with the subject ID specified and that subject does not exist, the subject is automatically created on data archive. That's fine, but the subject is created without any attributes set other than the project and subject IDs. The DICOM may contain useful demographic data that can be automatically mapped into the subject. The configuration for this mapping should be configurable to allow for flexibility in setting, e.g., birthdate (project may only want YOB or age range) and other attributes.