bi_sql_editor: add support for group operators

this commit allows specifying the group operator for each field. This functionality was originally included in a seperate module "bi_sql_editor_aggregate" in version 12.

bi_sql_editor/models/ir_model.py

@@ -0,0 +1,9 @@
+from odoo import models
+
+
+class IrModelFields(models.Model):
+    _inherit = "ir.model.fields"
+
+    def _add_manual_fields(self, model):
+        super()._add_manual_fields(model)
+        self.env["bi.sql.view"].check_manual_fields(model)