Resolve base model members for BaseModel instances

[trinhanhngoc]

Sometimes you need to annotate the type of an object as a recordset in general using BaseModel. In this situation it would be nice to support code completion and navigation for members from the base model as well since all models inherit it.

https://github.com/odoo/odoo/blob/a33dbdb5c7190205a88e253676a3b63fa22ad6f1/odoo/tests/form.py#L124 https://github.com/odoo/odoo/blob/a33dbdb5c7190205a88e253676a3b63fa22ad6f1/odoo/addons/base/models/ir_ui_view.py#L2505