Form Block: Add Credit Card Payment Field

### Impacted plugin

Jetpack

### What

The Forms block doesn't have payment integration. Having a credit card field would allow the creation of simple payment forms with a lot of flexibility.

### How

The ability to add a credit card field to a form would be extremely useful. It would allow users to accept payments for services, create a custom donate form, create a custom product form, etc.

I would have used this feature on multiple builds. An example from today which I was unable to build was a simple donation form with specific text fields, with payment integration. This could be achieved with WooCommerce and the custom fields plugin, but this shouldn't be so complicated or expensive to setup.

We can look at Gravity Forms to see examples of how this would be useful.

Gravity Forms shows their credit card field [here](https://href.li/?https://docs.gravityforms.com/credit-card-field/), and they have another page with examples of payment integrations [here](https://href.li/?https://www.gravityforms.com/wordpress-payments-made-easy/).

The benefit of having a credit card field connected to the form is the flexibility you have since you can add all the standard form fields. There would need to be a few extra fields, such as [product](https://href.li/?https://docs.gravityforms.com/product/), [quantity](https://href.li/?https://docs.gravityforms.com/quantity/), and [total](https://href.li/?https://docs.gravityforms.com/total/). This would enable you to sell multiple items from the same form, sell tickets to events, and more.

Being able to sell multiple products from the same form would benefit customers who have items to sell but aren’t ready to take the step to WooCommerce.

Gravity Form examples:

The issue names no Jetpack files, tests, or entry points. Start by reviewing the Forms block and the linked Gravity Forms examples to define the payment, product, quantity, and total requirements; done would require an agreed implementation scope and acceptance tests.

Written by the indexing model from the issue text.