* 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>
Removes the current value on focus, so that the user gets to see the available options. If no selection or change is made, the value is reset to the previous value on blur.
Closes#4154.
