remove unused build args, use env variables (#14)

frontend/svelte.config.js

@@ -1,6 +1,9 @@
 //import adapter from '@sveltejs/adapter-auto';
 import adapterNode from '@sveltejs/adapter-node';
 import { vitePreprocess } from '@sveltejs/kit/vite';
+import dotenv from 'dotenv';
+
+dotenv.config();
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
   kit: {