Added new Auth Source Null
Will only allow one Null Authentication Source
Will always return true when trying to authenticate
Make NullSource class exclusive
Added new class type exclusive
Added the Null Source type to the documentation
Added method getExclusiveSources
Added self registration mode null
Created drop down menus for each class type
Fixed issue with authentication and email required
Added the exclusive type to guest mode
Added new type null
Added support for a null authentication source
Changed the default for email_required to disabled
Added values for the checkbox
Added support for the null authentication source
Added support for the null authentication source