Use functions for logging load & save game times (#328)

Less copy and paste. Allows these very simple timings to be logged from elsewhere as well.

Ja2/TimeLogging.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "Types.h"
+
+void TimingLogInitialize(const CHAR8* filename);
+void TimingLog(const CHAR8* logEvent, int n);
+void TimingLogTotalTime(const CHAR8* logEvent, int n);
+void TimingLogWrite(const CHAR8* text);
+void TimingLogStop();