MXS-1220: Make nested resources links

If a resource can be accessed from more than one place, it should be a
link. The previous change that duplicated the content for nested resources
wasn't a very clean solution. With links, the content is easier to browse
using a normal browser.

include/maxscale/listener.h

@@ -20,6 +20,7 @@
 #include <maxscale/protocol.h>
 #include <maxscale/ssl.h>
 #include <maxscale/hashtable.h>
+#include <maxscale/jansson.h>
 
 MXS_BEGIN_DECLS
 
@@ -61,6 +62,15 @@ typedef struct servlistener
  */
 bool listener_serialize(const SERV_LISTENER *listener);
 
+/**
+ * @brief Convert listener to JSON
+ *
+ * @param listener Listener to convert
+ *
+ * @return Converted listener
+ */
+json_t* listener_to_json(const SERV_LISTENER* listener);
+
 SERV_LISTENER* listener_alloc(struct service* service, const char* name, const char *protocol,
                               const char *address, unsigned short port, const char *authenticator,
                               const char* auth_options, SSL_LISTENER *ssl);