Replace organizer_edit_tabs by nav_organizer

src/pretix/base/signals.py

@@ -1,3 +1,4 @@
+import warnings
 from typing import Any, Callable, List, Tuple
 
 import django.dispatch
@@ -52,6 +53,13 @@ class EventPluginSignal(django.dispatch.Signal):
         return responses
 
 
+class DeprecatedSignal(django.dispatch.Signal):
+
+    def connect(self, receiver, sender=None, weak=True, dispatch_uid=None):
+        warnings.warn('This signal is deprecated and will soon be removed', stacklevel=3)
+        super().connect(receiver, sender=None, weak=True, dispatch_uid=None)
+
+
 event_live_issues = EventPluginSignal(
     providing_args=[]
 )