Historically, OpenMRS requires names to contain a "Given" part and a "Family" part. But in the real world some places only use a single name. We should relax the constraint in OpenMRS to support this real-world use case.
Recently this was raised here: https://talk.openmrs.org/t/can-i-set-family-name-as-non-required-field/
Make changes in https://github.com/openmrs/openmrs-core/blob/2.0.1/api/src/main/java/org/openmrs/validator/PersonNameValidator.java so that only `givenName` is required (but `familyName` is allowed to be blank).
Also make changes in the relevant messages.properties files so that the error key and message reflect the new validation.
After making this change, we also need to make a related change in the REST Web Services module. This is captured in a different ticket:
We expect that making this change in the core API will automatically just work in different UIs built on top of this, but as part of signing off on the work on this issue, please verify that the new behavior works correctly when used with the Legacy UI module.