Add Expenses app

A UI based on [Budget Zen](https://github.com/BrunoBernardino/budgetzen-web) but slightly updated and adjusted for bewCloud. It also features a chart with available money and spent by budgets.

This is useful for envelope-based budgeting.

lib/utils/misc.ts

@@ -1,3 +1,6 @@
+import { currencyMap } from '/lib/types.ts';
+import { SupportedCurrencySymbol } from '/lib/types.ts';
+
 let BASE_URL = typeof window !== 'undefined' && window.location
   ? `${window.location.protocol}//${window.location.host}`
   : '';
@@ -256,3 +259,12 @@ export const capitalizeWord = (string: string) => {
 export function getRandomItem<T>(items: Readonly<Array<T>>): T {
   return items[Math.floor(Math.random() * items.length)];
 }
+
+export function formatNumber(currency: SupportedCurrencySymbol, number: number) {
+  return new Intl.NumberFormat('en-US', {
+    style: 'currency',
+    currency: currencyMap.get(currency) || 'USD',
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 2,
+  }).format(Number.parseFloat(`${number}`.replace(',', '.')));
+}