feat: Add intersex option for animals

Intersex rats are rare but well documented.

src/fellchensammlung/migrations/0024_alter_animal_sex.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.1.1 on 2024-11-21 19:34
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fellchensammlung', '0023_user_email_notifications'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='animal',
+            name='sex',
+            field=models.CharField(choices=[('M_N', 'neutered male'), ('M', 'male'), ('F_N', 'neutered female'), ('F', 'female'), ('I', 'intersex')], max_length=20),
+        ),
+    ]