improve description of the apiKeyValue argument in the config.ini

Author: Helene

source/config.ini

@@ -32,7 +32,11 @@ serverPort = 9980
 apiKeyName = scale_grafana
 
 # The REST HTTPS API key value, f.e:
-# 	apiKeyValue = e40960c9-de0a-4c75-bc71-0bcae6db23b2
+#   apiKeyValue = e40960c9-de0a-4c75-bc71-0bcae6db23b2
+#
+# alternatively you can store a string of 32 hexadecimal digits in a file
+# and specify the file location as the REST HTTPS API key value, f.e:
+#   apiKeyValue = /etc/bridge_ssl/apikey_scale-21
 
 #################################### GPFS Server data query settings ###########
 [query]