This commit provides hard constraints (SQL level) for expense to work in multi company environement. This is related to a R&D task, the rest of the code need to be adapt, but freeze is coming. As expense implies accounting entries, it is required to generate them in the right company, the company field should then be required. Task-1999686 closes odoo/odoo#35953 Signed-off-by: Jérome Maes (jem) <jem@openerp.com>