Treat service parameters as module parameters

The same mechanism that is used for modules can be used for the
configuration of the core objects. This removes the need for the redundant
code that validates various values that is already present in the code
that modules use.

server/modules/routing/binlogrouter/test/testbinlog.cc

@@ -107,7 +107,7 @@ int main(int argc, char **argv)
     set_libdir(MXS_STRDUP_A("../../../authenticator/MySQLBackendAuth/"));
     load_module("MySQLBackendAuth", MODULE_AUTHENTICATOR);
 
-    if ((service = service_alloc("test_service", "binlogrouter")) == NULL)
+    if ((service = service_alloc("test_service", "binlogrouter", NULL)) == NULL)
     {
         printf("Failed to allocate 'service' object\n");
         return 1;