Impacted versions: Master - probably all

Steps to reproduce:
Go to Settings Screen

Current behavior:
You'll see Authentification written twice.  In English, and especially in English technology speak the usual word is Authentication.

The only real issue it causes is that when searching for docs, you would search for Authentication (e.g. "How do I setup Oauth Authentication with provider x?"

Expected behavior:

Video/Screenshot link (optional):
![image](https://user-images.githubusercontent.com/5093264/29589757-99092af0-87ea-11e7-8bbe-dd8593b54d42.png)

Seems it occurs 4 times in code, but didn't want to PR as I don't understand translations
![image](https://user-images.githubusercontent.com/5093264/29589851-1e30f71c-87eb-11e7-94a7-fdb16a9eeccf.png)

FIx if you want, close if you want, I won't be offended and can manage


super(ResConfigSettings, self).set_values()
        self.env['ir.config_parameter'].sudo().set_param("base_setup.default_external_email_server", self.default_external_email_server)
        self.env['ir.config_parameter'].sudo().set_param("base_setup.default_user_rights", self.default_user_rights)
        self.env['ir.config_parameter'].sudo().set_param("base_setup.default_custom_report_footer", self.default_custom_report_footer)
        self.env.ref('base.res_partner_rule').write({'active': not self.company_share_partner})
    @api.multi
    def open_company(self):
        return {
            'type': 'ir.actions.act_window',
            'name': 'My Company',
            'view_type': 'form',
            'view_mode': 'form',
            'res_model': 'res.company',
            'res_id': self.env.user.company_id.id,
            'target': 'current',
        }
    @api.multi
    def open_default_user(self):
        action = self.env.ref('base.action_res_users').read()[0]
        action['res_id'] = self.env.ref('base.default_user').id
        action['views'] = [[self.env.ref('base.view_users_form').id, 'form']]
        return action
    @api.model
    def _prepare_report_view_action(self, template):