MXS-553: List connections in sessions resource

The connections that relate to a particular session are now a part of the
sessions resource. Currently, only the generic information is stored for
each connection (id and server name).

include/maxscale/dcb.h

@@ -400,6 +400,15 @@ int dcb_get_port(const DCB *dcb);
  */
 DCB* dcb_get_current();
 
+/**
+ * Get JSON representation of the DCB
+ *
+ * @param dcb DCB to convert to JSON
+ *
+ * @return The JSON representation
+ */
+json_t* dcb_to_json(DCB* dcb);
+
 /**
  * DCB flags values
  */