Issue #2143519 by yched, Wim Leers: Allow FieldInstance yml files to refer to the Field by field name rather than by field_uuid.

Revert "Issue #2143519 by yched: Allow FieldInstance yml files to refer to the Field by field name rather than by field_uuid."

This reverts commit f2e66e87.

Issue #2143519 by yched: Allow FieldInstance yml files to refer to the Field by field name rather than by field_uuid.