[Feature]: Add Adyen to the demo page

[Frodigo]

How the project can be improved?

Add Adyen to our demo storefront to show which payment methods we support.

https://docs.vuestorefront.io/adyen/magento2/

What are the acceptance criteria?

• [ ]

Additional information

No response

Code of Conduct

• [X] I agree to follow this project's Code of Conduct