Move uuid to //aos:uuid

It is getting usage significantly further outside the logger.  Time to
promote it somewhere better.  I only see it getting used more.

Change-Id: I754739347212f5a3154f68c7b7fc84b9a9074d90
diff --git a/aos/events/logging/log_namer.h b/aos/events/logging/log_namer.h
index 2d4c23e..8f3f712 100644
--- a/aos/events/logging/log_namer.h
+++ b/aos/events/logging/log_namer.h
@@ -9,7 +9,7 @@
 
 #include "aos/events/logging/logfile_utils.h"
 #include "aos/events/logging/logger_generated.h"
-#include "aos/events/logging/uuid.h"
+#include "aos/uuid.h"
 #include "flatbuffers/flatbuffers.h"
 
 namespace aos {