Remove __id from every response of api-tabular

[geoffreyaldebert]

Internal column __id exists on every tables that api-tabular will query.

This column does not need to be displayed to users as it is only for internal purposes.

We propose to remove it by default for every API call.

[geoffreyaldebert]

finally, i wonder if it is a problem. It can be useful for the future to get this property. We won't display it on explore.data.gouv.fr and we can explain in our swagger that it is an internal primary key

[maudetes]

(il apparaît dans les exports csv, ce qui rajouterait donc une colonne non souhaitée?)