Introduced new callback interface for use with certain authentication methods.
Added LdapEntryIdentification to wrap the full identification of an LDAP entry (absolute and relative DNs)
Added LdapEntryIdentificationContextMapper.
LDAP-140: Added bindmethod in LdapTemplate and SimpleLdapTemplate that take a DirContextOperations instance and
uses the information from that instance (DN and Attributes) to perform the bind.