Add a server setting that sets the default for "Add Original Name" upload option server wide

[git4o]

I would like for there to be a server setting "Add Original Name" to be on in the upload options for all users by default. This removes confusion for new users and adds convenience for users that cleared their browser cookies. This could be a setting in the admin page. User would still be able to turn it off in upload options if they wish. Imo, this should be the default, because having random filenames is really annoying.

Yes, I saw #570 , this feature request is for admins to set the default for users