SONAR-4756 Document profiling level property in config file

sonar-application/src/main/assembly/conf/sonar.properties

@@ -181,3 +181,10 @@ sonar.jdbc.timeBetweenEvictionRunsMillis=30000
 
 # Delay (in seconds) between processing of notification queue
 sonar.notifications.delay=60
+
+#--------------------------------------------------------------------------------------------------
+# PROFILING
+# Level of information displayed in the logs: NONE (default), BASIC (functional information) and FULL (functional and technical details)
+#sonar.log.profilingLevel=NONE
+
+