Create a macro for module declarations

The modules are now declared with a common macro. This allows future
additions to the module loading process while also making the loaded
symbol name a constant.

server/modules/protocol/telnetd/telnetd.c

@@ -81,7 +81,7 @@ static void telnetd_echo(DCB *dcb, int enable);
  *
  * @return The module object
  */
-MODULE_INFO* GetModuleObject()
+MODULE_INFO* MXS_CREATE_MODULE()
 {
     MXS_INFO("Initialise Telnetd Protocol module.");