Py3: Replace six.moves imports

Replace six.moves and six.StringIO/BytesIO imports with cannonical
Python 3 packages.

Note: six.moves.input behaves differently than builtin input function.
Therefore I left six.moves.input for now.

See: https://pagure.io/freeipa/issue/7715
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>

ipapython/ipaldap.py

@@ -29,12 +29,9 @@ from copy import deepcopy
 import contextlib
 import os
 import pwd
+from urllib.parse import urlparse
 import warnings
 
-# pylint: disable=import-error
-from six.moves.urllib.parse import urlparse
-# pylint: enable=import-error
-
 from cryptography import x509 as crypto_x509
 
 import ldap