disable default developer

The main reason for this is, that after initial installation we do not leave the default `developer` open, for usage.

Now, with this change the admin does explicitly need to activate the account before it can be used


*Note:* Another option is to not even create the developer user/account upon installation. We just have the role defined in the `ups-realm.json` file.


Once this has been merged to master/1.0.x, I will go ahead and update the documentation