* Opt-in for new checkout
* Update wording
* Create invoice view update
* Remove jQuery from checkout testing code
* Checkout v2 basics
* WIP
* WIP 2
* Updates and fixes
* Updates
* Design updates
* More design updates
* Cheating and JS fixes
* Use checkout form id whenever invoices get created
* Improve email form handling
* Cleanups
* Payment method exclusion cases for Lightning and LNURL
TODO: Cases and implementation need to be discussed
* Introduce CheckoutType in API and replace UseNewCheckout in backend
Co-authored-by: nicolas.dorier <nicolas.dorier@gmail.com>
The custom amount option was disabled by default in #4126. This requires some additional adaptations in the post action as otherwise the invoice won't be generated.
Fixes#4183.
