Don't allow new users to upload diagrams directly

[slashme]

Suggestion by User:Pi.1415926535

Because there is constant abuse of the upload function, it would be a good idea to restrict it so that new users can't upload directly.

[Gouvernathor]

This is largely taken care of by the new restriction on Commons that non-Autopatrolled users (and not a lot of users are autopatrolled) cannot overwrite other users' images - you can't even overwrite your own which is kind of stupid. And that also applies when you try it through our OAuth.
There's still the possibility for people to spam new entries with new names each time, but he response to that should probably be a ban of the user and not a restriction on the tool that will in any case be hard to implement.