[IMP] base: introduce "_is_portal" on res.users

This commit introduces a "_is_portal" method complementary to the existing
"_is_internal" and "_is_public".

The goal is to ease usage through the code base and be able to easily
distinguish our 3 main use cases: public, portal and internal users.

Task-3056280

closes odoo/odoo#120827

Related: odoo/enterprise#38575
Related: odoo/upgrade#4575
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

odoo/addons/base/models/res_users.py

@@ -1031,6 +1031,10 @@ class Users(models.Model):
         self.ensure_one()
         return not self.sudo().share
 
+    def _is_portal(self):
+        self.ensure_one()
+        return self.has_group('base.group_portal')
+
     def _is_public(self):
         self.ensure_one()
         return self.has_group('base.group_public')