[feat]: Create Checkout Session + Redirect to Stripe Checkout Page (when payment button is clicked)

[henrylee746]

Description

Instead of building a custom credit card form, use Stripe Checkout (prebuilt page) to handle PCI compliance and UI.
Create a Server Action (would probably be easier) or API Route to generate a hosted payment URL (and the session)

This should be triggered when the user clicks on the "Make Payment" button

Can then use the URL to redirect the user to Stripe's hosted checkout page (once the session is created)