Adding first and last name to sponsor model

Adding first and last name to sponsor model so that we don't have to ask a different service for these.

Adding some auto-generated endpoints for adding and removing sponsors.

I just updated the initial migration instead of creating a new one.

greg/migrations/0001_initial.py

-# Generated by Django 3.2.5 on 2021-08-12 10:52
+# Generated by Django 3.2.5 on 2021-08-19 12:47
 
 import datetime
 import dirtyfields.dirtyfields
@@ -157,9 +157,6 @@ class Migration(migrations.Migration):
                 ('role', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='person_roles', to='greg.role')),
                 ('unit', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='unit_person_role', to='greg.organizationalunit')),
             ],
-            options={
-                'abstract': False,
-            },
             bases=(dirtyfields.dirtyfields.DirtyFieldsMixin, models.Model),
         ),
         migrations.CreateModel(
@@ -211,6 +208,10 @@ class Migration(migrations.Migration):
             model_name='sponsor',
             constraint=models.UniqueConstraint(fields=('feide_id',), name='unique_feide_id'),
         ),
+        migrations.AddConstraint(
+            model_name='personrole',
+            constraint=models.UniqueConstraint(fields=('person_id', 'role_id', 'unit_id', 'start_date', 'end_date'), name='person_role_unique'),
+        ),
         migrations.AddConstraint(
             model_name='personconsent',
             constraint=models.UniqueConstraint(fields=('person', 'consent'), name='person_consent_unique'),