Feature: Add End 2 End tests

[Davycontrolaltdelete]

Hello,

To improve the stability of this open source project, I've create this pull request together @https://github.com/michielgerritsen to add End 2 End tests. The added Github Action does the following:

• It sets up a Magento environment.
• It adds the Hyvä theme.
• It installs Magewire and https://github.com/magewirephp/magewire-examples.
• It runs Playwright against this environment.

During testing, the Magewire Examples page is used to check that everything is working as expected. These tests are included:

• Adding todos. Editing seems broke so we've skipped that.
• Test the shuffle function. In rare cases this might fail as it could that the new order is the same as the old order.
• Clicking the previous and next button for the pagination.
• Validating data, with both invalid and valid data.
• Adding and subtracting numbers.

To install Hyvä in the pipeline we've added a private key to Hyvä's Gitlab so we could install it. To merge this, the SSH_PRIVATE_KEY secret must be added, which should be in a id_ed25519 format.

There is probably more to test, but the main goal was to get some test up & running to be able to expand from that.

[wpoortman]

Thanks @Davycontrolaltdelete ! really love this and will try to look at it as soon as possible 💟