feat: add label to session for anonymous sessions (#1240)

This will allow, for example, to create dedicated
network policies that applies specifically to these
sessions.

The safe username label cannot be used in this context
as the label filter does not support regexp expressions.

Author: sgaist

components/renku_data_services/notebooks/core_sessions.py

@@ -1046,6 +1046,9 @@ async def start_session(
 
     labels = {"renku.io/safe-username": user.id}
 
+    if user.is_anonymous:
+        labels["renku.io/anonymous-session"] = "true"
+
     session = AmaltheaSessionV1Alpha1(
         metadata=Metadata(name=server_name, annotations=annotations),
         spec=AmaltheaSessionSpec(