[REF] hr: remove login and last_login fields on employee model

Those fields are never used anywhere. Moreover attendance module can be
used to track employee log in / log out and compute its attendances.
Let us therefore remove those fields.

addons/hr/models/hr.py

@@ -145,8 +145,6 @@ class Employee(models.Model):
     passport_id = fields.Char('Passport No')
     color = fields.Integer('Color Index', default=0)
     city = fields.Char(related='address_id.city')
-    login = fields.Char(related='user_id.login', readonly=True)
-    last_login = fields.Datetime(related='user_id.login_date', string='Latest Connection', readonly=True)
 
     # image: all image fields are base64 encoded and PIL-supported
     image = fields.Binary("Photo", default=_default_image, attachment=True,

addons/hr/views/hr_views.xml

@@ -160,7 +160,6 @@
         <field name="priority">10</field>
         <field name="arch" type="xml">
             <kanban class="o_hr_employee_kanban">
-                <field name="last_login"/>
                 <field name="message_is_follower"/>
                 <field name="message_follower_ids"/>
                 <field name="message_ids"/>