AuthBased*Provider try to use SortedSet without Comparable items
Description
`org.jivesoftware.openfire.user.AuthorizationBasedUserProviderMapper` and its `Auth` counterpart return a Set of providers, which needs to have a predictable iteration order. To do that, a SortedSet is used. As the providers do not implement Comparable, this causes exceptions.
`org.jivesoftware.openfire.user.AuthorizationBasedUserProviderMapper` and its `Auth` counterpart return a Set of providers, which needs to have a predictable iteration order. To do that, a SortedSet is used. As the providers do not implement Comparable, this causes exceptions.