Add/remove "Administer System" permission of default organization must set/unset users as root

setting/removing "Administer System" of the default organization must also set/unset the user as root

• when directly adding/removing the permission to a user
  • api/permissions/add_user
  • api/permissions/remove_user
• when adding the permission to a group (all users in the group must be set root)
  • api/permissions/add_group
• when removing the permission from a group (all users in the group must be unset root unless they have the "Administer System" permission by some other mean)
  • api/permissions/remove_group
• when adding a user to a group with the permission (the user must be set root)
  • api/user_groups/add_user
• when removing a user from a group with the permission (the user must be unset root unless she has the "Administer System" permission by some other mean)
  • api/user_groups/remove_user
• when creating a new user and default group has "Administer System" permission
• when removing a group
  • api/user_groups/delete
  • api/users/create
• when user is assigned or remove from group through the IdentitiyProvider