Refs #775 -- Pluggable authentication backends (#1447)

* Drag-and-drop: Force csrf_token to be present

* Rough design

* Missing file

* b.visble

* Forms

* Docs

* Tests

* Fix variable

src/pretix/control/forms/users.py

@@ -56,6 +56,10 @@ class UserEditForm(forms.ModelForm):
         super().__init__(*args, **kwargs)
         self.fields['email'].required = True
         self.fields['last_login'].disabled = True
+        if self.instance and self.instance.auth_backend != 'native':
+            del self.fields['new_pw']
+            del self.fields['new_pw_repeat']
+            self.fields['email'].disabled = True
 
     def clean_email(self):
         email = self.cleaned_data['email']