Add Simple RBF Transaction Cancellation

Trezor Suite offers a user-friendly "Cancel" button to cancel unconfirmed Bitcoin transactions using Replace-By-Fee (RBF), automatically creating a "send-to-self" transaction with a higher fee to replace the original. Sparrow and other wallets also support RBF cancellation, but Sparrow’s approach involves manual steps, which is less intuitive.

Implementing a streamlined "Cancel" button in Green QT, similar to Trezor Suite, would simplify managing stuck transactions or errors before confirmation. This would enhance user experience and align Green with wallets like Trezor and Sparrow. Please consider adding this feature.