[IMP] account: payment method improvements

To improve the payment method system, proceed to a few changes
such as changing the view a bit, making sure payment acquirers are not
linked to a journal by default and that only the manual payment method
type can be used multiple times in a single journal.

Task id #2573145

closes odoo/odoo#73596

X-original-commit: 9122b367baea10e59b66e45bf7c458a6f1e82efb
Related: odoo/enterprise#19623
Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>