Add function for adding base data and data reloading.

dsst/dsst_gtk3/handlers/center_handlers.py

@@ -0,0 +1,10 @@
+from dsst_gtk3.gtk_ui import DSSTGtkUi
+from dsst_sql import sql
+from dsst_gtk3 import dialogs, util
+
+class CenterHandlers:
+    def __init__(self, app: DSSTGtkUi):
+        self.app = app
+
+    def do_add_death(self, *_):
+        pass