Create Node Server 'Logs' directory on demand.  Fixes #2828

This PR includes two fixes.  

1) Previously the node server log writestream was instantiated when the server log level was >=2 (hardcoded).  This has been changed to on-demand, only create the log file when needed.

2) Logging failed if the ./Logs directory did not exist.  Now the ./Logs directory is created on demand if it doesn't exist.