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 
Not sure I follow, having a large number of returns still would result in a highly complex function. Can you describe in English what this function does? Again, not blocking, but if we can't describe what the method does, then it really is too complex.