Users loggedOn log

A facility to log all "user logging on" functions is implemented. The facility is turned ON/OFF by the EDMconfigurationVariable LOGGING_LOGGED_ON_USERS. The value TRUE turns the logging on and FALSE terminates a logging session. A sampling interval can be specified. The sampling (means writing accumulated result to the actual log file) is performed by the EDMserverBackupThread, hence this functionality is not applicable when the EDMserverBackupThread is not running. The actual result is date&time for first logged on, number of times logged on, last time logged on, date&time for interval with most logged on times (peak interval), number of times logged on in peak interval. The format of the EDMconfigurationVariable LOGGING_LOGGED_ON_USERS value: LOGGING_LOGGED_ON_USERS = "TRUE ; 10" means Start "users loggedOn log" with 10 minutes sampling interval. The result log can be read at any time using the same functionality as for reading the EDMserverReportFile, i.e., the "getServerFile" functions. The result can be a formatted text file or a "tab separated text file". More convenient XPX functions for handling the log result may be implemented later.