Splitoff admin only roles for API

[vmcj]

We had this request both during EUC and this would help during next BAPC prelims where we probably ask a BAPC jury member to upload the problems already.

For the 2nd case I would personally trust that person with admin access but others might see that differently. Also only giving the needed access is always a good thing and given that this is easy to test I don't think this would be a real feature creep.