Use classes alongside data-hook attributes for gateway partial

[aitbw]

Description

Given that other fields in the aforementioned partial have data-hook attributes and classes to allow easy customization, I think it could be good that card-related fields have the same structure

Rebased version of #2212, all the credit goes to @ccarruitero

Checklist:

• I have followed Pull Request guidelines
• I have added a detailed description into each commit message
• I have updated Guides and README accordingly to this change (if needed)
• I have added tests to cover this change (if needed)

[kennyadsl]

I'm ok adding a class for card_name but I'd not remove existing data-hook.

[aitbw]

Done @kennyadsl ✔️ I don't know if it's necessary to squash the commits and/or change the PR's title, let me know what you think

[jacobherrington]

I would prefer it if you would squash the commits, but otherwise looks good to me. 👍

[kennyadsl]

I'd also go for squashing commits, thanks @aitbw!

[aitbw]

@kennyadsl @jacobherrington squashed!

[tvdeyen]

I am fine with adding css classes, but not with adding new data-hook attributes.

[jacobherrington]

I am happy with this as it is. Thanks!