Improve menu form

[atjn]

Improvements to the product buying form in the user menu:

• No longer uses JS.
• Page size is much smaller.
• Form is much more accessible.

There are no visual changes, except for some edge cases.

Instead of creating a new form for each product, we create a single form with a custom submit button for each product. Because we don't have to create 1000 forms, we save a lot of bandwidth. This also contributes to accessibility, since the browser can assert that this is a single form with different options, rather than a thousand separate forms that might not be related to each other.

Instead of using a link that invokes JS to submit a form, we use a button that natively submits the form. This is a big accessibility improvement, as it is now clear that the button is related to the form, and it is clear that the product name in the button is highly relevant.

[krestenlaust]

Nice👍