Remove "administrator" as a selectable role to allow access to

@Grevil: That's not correct, I think. You're mixing up Administrator with User 1 which is not the same. User 2 with "Administrator" will only have administrator permissions, not ANY permissions.

See 📌 Add a container parameter that can remove the special behavior of UID#1 Fixed (which will not be done in the next 10Y I guess :D)