Use study status properly

This blocks the attachment of raw data to the study until after the study metadata is approved. It also adds two buttons for admins to approve a study and to make a study public.

This finishes #476 
After an interesting discussion between @ElDeveloper @antgonza @adamrp and me we get to the point that the user can make it's own study public. The point is that after sandboxed, the metadata has been accepted, and the user is not able to do anything else, besides sharing the study and running analysis. Thus, the user can make the study public, since the admin has nothing to check.