*Draft until https://github.com/odoo/odoo/pull/35702 and it's enterprise counterpart are merged.*

This adds a pos_tipping module which defines some generic code meant
to handle tipping.

One part which is common in restaurants/bars allows a user to add a
tip after the order is completed. This will result in the total + that
tip being captured.

Another part is meant for easily retrieving orders in a bar
environment. When everybody orders drinks at the bar it's hard to keep
track of all the tabs. This adds an "Open Tab" button which does two
things:

- Authorizes the current order amount on the credit card, this way we
validate the card is good. This amount will be cancelled at the end.
- Associates the card holder's name to the order. This name can be
used in a new interface that allows searching for an order by name.

This also includes pos_adyen_tipping which is a concrete
implementation for Adyen. Adyen needs to be configured to Manual
Capture mode for this to work. Additionally Adyen needs to be
configured to allow overcaptures (capturing more than what was
initially authorized) to handle tips.

https://www.odoo.com/web?debug#id=1935923&action=327&model=project.task&view_type=form&menu_id=4720