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/monitor/mysqlmon/mysql_mon.c

@@ -45,6 +45,8 @@
  * @endverbatim
  */
 
+#define MXS_MODULE_NAME "mysqlmon"
+
 #include "../mysqlmon.h"
 #include <maxscale/dcb.h>
 #include <maxscale/modutil.h>