Logging in millisecs

After change to Akka consensus in NEO 3.0, it's so fast that seconds do not mean much anymore.. now milliseconds is important to actually know of what is going on the consensus algorithm.

SimplePolicy/SimplePolicyPlugin.cs

@@ -52,7 +52,7 @@ void ILogPlugin.Log(string source, LogLevel level, string message)
         {
             if (source != nameof(ConsensusService)) return;
             DateTime now = DateTime.Now;
-            string line = $"[{now.TimeOfDay:hh\\:mm\\:ss}] {message}";
+            string line = $"[{now.TimeOfDay:hh\\:mm\\:ss\\.fff}] {message}";
             Console.WriteLine(line);
             if (string.IsNullOrEmpty(log_dictionary)) return;
             lock (log_dictionary)