This commit adds a `custom_mode` field to payment acquirers to allow distinguishing the different payment modes made possible through the `payment_custom` module: Wire Transfer, Cash on Delivery, On-site picking. This avoids making direct references to the modules' data when trying to figure out which acquirer is which, hence allowing duplicating the acquirers in multi-company databases. task-2853489 closes odoo/odoo#99400 Related: odoo/upgrade#3847 Related: odoo/enterprise#30966 Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>