Add support for Hyvä Checkout

[kweij]

We want to make use of the Hyvä Checkout, which is an alternative to Luma-based checkout, delivers a huge improvement in performance and is built on current tech (Tailwind, AlpineJS, Livewire/Magewire).

However, in order to be able to continue using Adyen, the integration with Magento needs to support the Hyvä Checkout. I would love to see official support for the Hyvä Checkout provided by Adyen itself.

The community of developers working with Hyvä is growing and so is the number of shops using it. Hyvä provides a community built integration module for Adyen. I have tried it, but it is incomplete and troubled with blocking issues preventing us from using it. Also, this module only supports Adyen v8, preventing us from upgrading the Adyen payments module.

Please take the the shops based on Hyvä in consideration for official support ❤️

Edit: I got the community built integration module I mentioned working (with some patches).