Closes #13299: Improve options for controlling custom field visibility (#14289)

* Add ui_visible and ui_editable fields

* Extend migration to map new visible/editable values

* Remove ui_visibility field

* Update docs

netbox/extras/migrations/0100_customfield_ui_attrs.py

@@ -0,0 +1,41 @@
+from django.db import migrations, models
+
+
+def update_ui_attrs(apps, schema_editor):
+    """
+    Replicate legacy ui_visibility values to the new ui_visible and ui_editable fields.
+    """
+    CustomField = apps.get_model('extras', 'CustomField')
+
+    CustomField.objects.filter(ui_visibility='read-write').update(ui_visible='always', ui_editable='yes')
+    CustomField.objects.filter(ui_visibility='read-only').update(ui_visible='always', ui_editable='no')
+    CustomField.objects.filter(ui_visibility='hidden').update(ui_visible='hidden', ui_editable='hidden')
+    CustomField.objects.filter(ui_visibility='hidden-ifunset').update(ui_visible='if-set', ui_editable='yes')
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('extras', '0099_cachedvalue_ordering'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='customfield',
+            name='ui_editable',
+            field=models.CharField(default='yes', max_length=50),
+        ),
+        migrations.AddField(
+            model_name='customfield',
+            name='ui_visible',
+            field=models.CharField(default='always', max_length=50),
+        ),
+        migrations.RunPython(
+            code=update_ui_attrs,
+            reverse_code=migrations.RunPython.noop
+        ),
+        migrations.RemoveField(
+            model_name='customfield',
+            name='ui_visibility',
+        ),
+    ]