Add definitions of MXS_MODULE_NAME to all modules

All modules now declare a name for the module. This is name is added as a
prefix to all messages logged by a module. The prefix should help
determine which part of the system logs a message.

server/modules/routing/avrorouter/avro_client.c

@@ -24,6 +24,8 @@
  * @endverbatim
  */
 
+#include "avrorouter.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
@@ -37,7 +39,6 @@
 #include <maxscale/spinlock.h>
 #include <maxscale/log_manager.h>
 #include <maxscale/version.h>
-#include "avrorouter.h"
 #include <maxavro.h>
 #include <maxscale/alloc.h>