[IMP] account: misc improvement post accountappocalypse

* remove _onchange_invoice_date_due as it is superseeded by _onchange_recompute_dynamic_lines
* change invoice_date_due only if not set and if there is no payment term, it was erased and set to invoice_date_due if we did not set invoice_date_due before posting
* raise a warning if we validate an empty move/invoice
* correct the renaming of user_id -> invoice_user_id in invoice template
* correct the renaming of date_invoice -> invoice_date
* the data on purchase journals was not displayed correctly as the sign
of the amount in the graphs was not signed correctly
* the methods for computed invoice reference were not correctly renamed in l10n_be for (account.move)._get_invoice_computed_reference
* the default reconciliation model was only installed in the first company, we make it now install along with the chart of account
* the partner of invoices and the label of invoice lines should be required
* the widget one2many_list doesn't exist

closes odoo/odoo#34786

Signed-off-by: Cedric Snauwaert (csn) <csn@openerp.com>