DistinguishedName comparison should only be about hierarchy relation

[adiroiban]

See this test which now pass, but which I think should raise an exception as you should not compare such elements

I don't have a use case for such a comparison.

I am opening this issue to gather feedback

https://www.ldap.com/ldap-dns-and-rdns

Most LDAP client APIs offer some mechanism for comparing DNs (e.g., to determine whether they are equal, or to determine whether they are hierarchically related)

    def test_parent_unrelated(self):
        """
        Children from different parents should not be compared

        This pass now
        """
        dn1=dn.DistinguishedName('dc=ab,dc=abc,dc=com')
        dn2=dn.DistinguishedName('dc=ba,dc=example,dc=com')

        self.assertLess(dn1, dn2)