Add support for hash_password

pillar.example

     # WARNING: If 'empty_password' is set to True, the 'password' statement
     # will be ignored by enabling password-less login for the user.
     empty_password: False
+    hash_password: False
     system: False
     home: /custom/buser
     homedir_owner: buser

users/init.sls

     {% if 'enforce_password' in user -%}
     - enforce_password: {{ user['enforce_password'] }}
     {% endif -%}
+    {% if 'hash_password' in user -%}
+    - hash_password: {{ user['hash_password'] }}
+    {% endif -%}
     {% if user.get('system', False) -%}
     - system: True
     {% endif -%}