- Proxy user is no longer a computed store=True field, but a proper one.
The type cannot be deduced just by some field on the company.
A company may be Italian and also use Peppol, so the two Proxy Users
must be different.
- The Proxy user `get_proxy_identification` method needs a proxy_type
argument, otherwise the method won't know if the current override
is to be applied or not. It cannot be handled by a field of the user
itself because it is also used contextually to the user creation.
- new `_get_default_enable_send_by_post` function on the Send and Print
wizard, so that it can be overridden by the features of the move
- Renamed `_compute_send_mail_extra_fields`
to `_compute_fields_from_moves_state`
Part-of: odoo/odoo#122194