ipauser: Add support for SMB attributes.

Since FreeIPA version 4.8.0 ipauser has support for smb-logon-script,
smb-profile-path, smb-home-dir, and smb-home-drive drive attributes.

On FreeIPA, these attributes are only available when modifying a user,
so if the user defined in the playbook does not exist, two calls to IPA
API are executed, a 'user_add' followed by a 'user_mod'.
(see https://github.com/freeipa/freeipa/blob/master/doc/designs/adtrust/samba-domain-controller.md

A new example playbook can be found at:

     playbooks/user/smb-attributes.yml

A new test playbook can be found at:

     tests/user/test_user_smb_attrs.yml