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/network/BUILD b/aos/network/BUILD
index 8e7d476..789b093 100644
--- a/aos/network/BUILD
+++ b/aos/network/BUILD
@@ -148,7 +148,7 @@
         "//aos:configuration",
         "//aos:flatbuffer_merge",
         "//aos:flatbuffers",
-        "//aos/events/logging:uuid",
+        "//aos:uuid",
         "@com_github_google_flatbuffers//:flatbuffers",
     ],
 )