Add default parameters to created monitors

When a monitor is created at runtime, it also needs to have the default
parameters. Ideally, this would be done when the monitor is allocated but
because of the way the configuration is processed, we need to do it after
user defined parameters are added.

include/maxscale/config.h

@@ -265,6 +265,19 @@ const char* config_get_string(const CONFIG_PARAMETER *params, const char *key);
  */
 int config_get_enum(const CONFIG_PARAMETER *params, const char *key, const MXS_ENUM_VALUE *values);
 
+/**
+ * @brief Generate default module parameters
+ *
+ * Adds any default parameters to @c ctx that aren't already in it.
+ *
+ * @param ctx    Configuration context where the parameters are added
+ * @param module Module name
+ * @param type   Module type
+ *
+ * TODO: Move this to a header internal to the MaxScale core
+ */
+void config_add_defaults(CONFIG_CONTEXT *ctx, const char *module, const char *type);
+
 char*               config_clean_string_list(const char* str);
 CONFIG_PARAMETER*   config_clone_param(const CONFIG_PARAMETER* param);
 void                config_enable_feedback_task(void);