Add close and refresh keybinds

frontend/wailsjs/go/main/App.d.ts

@@ -3,6 +3,8 @@
 import {main} from '../models';
 import {time} from '../models';
 
+export function Close():Promise<void>;
+
 export function EmptyBill():Promise<main.Bill>;
 
 export function EmptyPayment():Promise<main.Payment>;

frontend/wailsjs/go/main/App.js

@@ -2,6 +2,10 @@
 // Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
 // This file is automatically generated. DO NOT EDIT
 
+export function Close() {
+  return window['go']['main']['App']['Close']();
+}
+
 export function EmptyBill() {
   return window['go']['main']['App']['EmptyBill']();
 }