Add config parameter reference for the method set_param()

[trinhanhngoc]

The Odoo plugin already supports config parameter reference for get_param(). Hence we also need support for set_param().

https://github.com/odoo/odoo/blob/5ca1b68ef9f5b31416cdfbeee6e984ca754d38cd/odoo/addons/base/tests/test_ir_attachment.py#L47