refactor!: serve the static frontend trough the backend (#520)

Co-authored-by: Alessandro (Ale) Segala <43508+ItalyPaleAle@users.noreply.github.com>

frontend/svelte.config.js

@@ -1,4 +1,4 @@
-import adapter from '@sveltejs/adapter-node';
+import adapter from '@sveltejs/adapter-static';
 import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
 import packageJson from './package.json' with { type: 'json' };
 
@@ -12,11 +12,14 @@ const config = {
 		// adapter-auto only supports some environments, see https://kit.svelte.dev/docs/adapter-auto for a list.
 		// If your environment is not supported, or you settled on a specific environment, switch out the adapter.
 		// See https://kit.svelte.dev/docs/adapters for more information about adapters.
-		adapter: adapter(),
+		adapter: adapter({
+			fallback: "index.html",
+			pages: process.env.BUILD_OUTPUT_PATH ?? "../backend/frontend/dist",
+		}),
 		version: {
 			name: packageJson.version
-		}
-	}
+		},
+	},
 };
 
 export default config;