UPDATE: split the webapp in a widget and the app itself

This splits the webapp in:

* IronCalc (the widget to be published on npmjs)
* The frontend for our "service"
* Adds "dummy code" for the backend using sqlite

webapp/app.ironcalc.com/frontend/vite.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import svgr from 'vite-plugin-svgr';
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [react(), svgr()],
+  server: {
+    fs: {
+      // Allow serving files from one level up to the project root
+      allow: ['../../../'],
+    },
+  },
+})