Refactor model layout

src/registrar/models/user_profile.py

@@ -0,0 +1,29 @@
+from django.db import models
+
+from .utility.time_stamped_model import TimeStampedModel
+from .utility.address_model import AddressModel
+
+from .contact import Contact
+from .user import User
+
+
+class UserProfile(TimeStampedModel, Contact, AddressModel):
+
+    """User information, unrelated to their login/auth details."""
+
+    user = models.OneToOneField(
+        User,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+    )
+    display_name = models.TextField()
+
+    def __str__(self):
+        # use info stored in User rather than Contact,
+        # because Contact is user-editable while User
+        # pulls from identity-verified Login.gov
+        try:
+            return str(self.user)
+        except Exception:
+            return "Orphaned account"