Option to export node input values

[georgevbsantiago]

Allow the node to export input values in a specific field/key so that it can be used in subsequent nodes.
This functionality would be very useful to know which inputs were filled in manually by the user and then be able to use the values in subsequent nodes.
(NOTE: We don't know if it would be better to place the field/key inside or outside the Payload. Perhaps the best option to avoid causing bugs is to export outside the payload).
See the suggestion below:

{
...
"payload": {array [ 278]},
            "_config_inputs_node": {"bucket": "XXXX",
                                    "tag": "XXXX",
                                    "filter": "XXXX",
                                    "timespan_sequence": "XXXX",
                                    "timespan_value":"XXXX",
                                    "timespan_units":"XXXX",
                                    "min_ts":"XXXX",
                                    ...
            }
}