Add Ldaptive support for Relay staff attributes

@frett 

Note this PR already includes the changes from https://github.com/GlobalTechnology/idm-user-management/pull/6
If you end up using cruPerson for staff only we will need another objectClass that captures relayGuid and any other attributes coming from Relay that are on all accounts.

I'll leave that decision up to you for your use cases.

I am going to push a minor change that removes the need for intermediate collection objects when creating the objectClass