[12.0][IMP] base_external_dbsource: Add company field to backend

fw-port from b7f439e04a

base_external_dbsource/models/base_external_dbsource.py

@@ -57,6 +57,11 @@ class BaseExternalDbsource(models.Model):
     - SQLite: sqlite:///test.db
     - Elasticsearch: https://user:%s@localhost:9200
     """)
+    company_id = fields.Many2one(
+        comodel_name='res.company',
+        string='Company',
+        default=lambda self: self.env.user.company_id,
+    )
     conn_string_full = fields.Text(
         readonly=True,
         compute='_compute_conn_string_full',