[BOOT:LIB] Add conditional debug printing

Added DebugPrint() and DebugPrintf() macros, which are aliases of
ConsolePrint() and ConsolePrintf() if _DEBUG is defined. Otherwise, they
do not generate any code.

BOOT/ENVIRON/INC/bootlib.h

@@ -34,6 +34,17 @@ ConsolePrintf (
     ...
     );
 
+//
+// Enable/disable debug printing.
+//
+#ifdef _DEBUG
+#define DebugPrint(String) ConsolePrint(String)
+#define DebugPrintf(Format, ...) ConsolePrintf(Format, __VA_ARGS__)
+#else
+#define DebugPrint(String)
+#define DebugPrintf(Format, ...)
+#endif
+
 ULONG
 BlGetBootOptionSize (
     IN PBOOT_APPLICATION_OPTION Option