Make it possible to hide certain datasets but expose their data

[cjhendrix]

@takavarasha suggested we might be able to make the /dataset/json-repository private but still use the data in our various custom pages. If we have a special user (let's call him bob) who is a member of a fake org owning any datasets we want to hide. Then we make any datasets we want to hide from search results private and the controllers can use Bob's api key to access their data and pass it on to the templates.

[danmihaila]

Why not making a /dataset/json-repository-private with datasets not to be shared or hidden by search. It will still be the question: we don't share private dataset, but use that data to create public visualizations/maps