Simplify folders and more typescript migration

src/config.mjs

@@ -1,3 +1,5 @@
+import defaultImage from './assets/images/default.png';
+
 export const SITE = {
 	name: 'AstroWind',
 
@@ -8,6 +10,8 @@ export const SITE = {
 	title: 'AstroWind — Your website with Astro + Tailwind CSS',
 	description: '🚀 AstroWind is a free and ready to start template to make your website using Astro and Tailwind CSS.',
 
+	defaultImage: defaultImage,
+
 	googleAnalyticsId: false, // or "G-XXXXXXXXXX",
 	googleSiteVerificationId: 'orcPxI47GSa-cRvY11tUe6iGg2IO_RPvnA1q95iEM3M',
 };