[helm] Allow setting notification.toml config (#6159)

* [helm] Allow setting notification.toml config

* [helm] Set notification config conditionally

k8s/charts/seaweedfs/values.yaml

@@ -546,6 +546,19 @@ filer:
   # Disable http request, only gRpc operations are allowed
   disableHttp: false
 
+  # Add a custom notification.toml to configure filer notifications
+  # Example:
+  # notificationConfig: |-
+  #   [notification.kafka]
+  #   enabled = false
+  #   hosts = [
+  #       "localhost:9092"
+  #   ]
+  #   topic = "seaweedfs_filer"
+  #   offsetFile = "./last.offset"
+  #   offsetSaveIntervalSeconds = 10
+  notificationConfig: ""
+
   # DEPRECATE: enablePVC, storage, storageClass
   # Consider replacing with filer.data section below instead.