Accounting users can now combine several vendor bills or invoices into a single payment flow, even across different partners or document types. This reduces repetitive payment processing work and makes bulk payment handling faster and easier.

Description of the issue/feature this PR addresses:

related to task:
https://www.odoo.com/web#id=24014&view_type=form&model=project.task&menu_id=

Current behavior before PR:

Desired behavior after PR is merged:

-Pay Multiple Vendor Bills at Once
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The SEPA payments module now allows more information to be passed when preparing payment values. This is a small internal enhancement that makes it easier to customize or extend SEPA payment handling without changing the core flow.

see task: https://www.odoo.com/web#id=24014&view_type=form&model=project.task&action=333&active_id=967&menu_id=4720

Invoice and sales order reports now show the taxable amount alongside each tax group when there are multiple invoice lines and multiple tax groups. This makes tax details easier for customers to understand and updates many country accounting setups to support the improved grouping.

The website shop and portal now use the same central VAT validation logic already available for partners. This reduces duplicated code, making future tax ID validation updates easier and less likely to behave inconsistently across customer-facing flows.

Avoid copy and paste code and repeated lines if a change is generated
from check_vat so we need to remember upgrade a copy and paste of all
models where is used this validation.

Use check_vat function directly help us to re-use 100% the code without
errors and inheritable.

"A good developer create code a better one re-use":
![re-use](https://user-images.githubusercontent.com/6644187/27189460-0a57fdfe-51b7-11e7-9685-bc3dd33eba8c.jpg)