raw output: add custom fields

This will include all configured custom fields in the raw output
under the "custom_fields" key.

output/raw/raw.go

@@ -14,6 +14,7 @@ type RawNode struct {
 	Statistics   *data.Statistics       `json:"statistics"`
 	Nodeinfo     *data.Nodeinfo         `json:"nodeinfo"`
 	Neighbours   *data.Neighbours       `json:"neighbours"`
+	CustomFields map[string]interface{} `json:"custom_fields"`
 }
 
 type NodeList struct {
@@ -37,6 +38,7 @@ func transform(nodes *runtime.Nodes) *NodeList {
 				Statistics:   nodeOrigin.Statistics,
 				Nodeinfo:     nodeOrigin.Nodeinfo,
 				Neighbours:   nodeOrigin.Neighbours,
+				CustomFields: nodeOrigin.CustomFields,
 			}
 			nodelist.List = append(nodelist.List, node)
 		}