Add NodeEventLoopFactory

This lets us create event loops on separate nodes which can't
communicate with each other.  Next step is to add a message proxy
between them, then teach the logger to replay onto multiple nodes.

Change-Id: I06b2836365aea13d696535c52a78ca0c862a7b1e
diff --git a/aos/configuration.h b/aos/configuration.h
index ef30fce..88687ad 100644
--- a/aos/configuration.h
+++ b/aos/configuration.h
@@ -69,6 +69,9 @@
 const Node *GetNodeFromHostname(const Configuration *config,
                                 std::string_view name);
 
+// Returns true if we are running in a multinode configuration.
+bool MultiNode(const Configuration *config);
+
 // Returns true if the provided channel is sendable on the provided node.
 bool ChannelIsSendableOnNode(const Channel *channel, const Node *node);
 // Returns true if the provided channel is able to be watched or fetched on the