Refactor starter_cmd a bit

This patch switches the order of arguments for starter_cmd. In
particular, the subcommand now comes first and then you specify the
name of the application.

For example:

  $ starter_cmd start <app>
  $ starter_cmd stop <app>
  $ starter_cmd status <app>

This patch also enhances the "status" command to work without any
arguments. In this case, it will print out a high-level status for all
applications.

The error reporting on incorrect arguments to starter_cmd should also
be quite a bit improved with this change.

Change-Id: I4c80e6662b6f3d3e630a4be26d579e1166a89643
diff --git a/aos/starter/starter_rpc_lib.h b/aos/starter/starter_rpc_lib.h
index 57c9e6b..152016a 100644
--- a/aos/starter/starter_rpc_lib.h
+++ b/aos/starter/starter_rpc_lib.h
@@ -30,6 +30,11 @@
 const aos::FlatbufferDetachedBuffer<aos::starter::ApplicationStatus> GetStatus(
     std::string_view name, const aos::Configuration *config);
 
+// Fetches the entire status message of starter. Creates a temporary event loop
+// from the provided config for fetching.
+const aos::FlatbufferVector<aos::starter::Status> GetStarterStatus(
+    const aos::Configuration *config);
+
 }  // namespace starter
 }  // namespace aos