Vercel Proxying: add config to test proxying

We'd like to try experimenting with pointing www.ifixit.com at vercel
and have vercel proxy any missed routes to our main php app.

Before we make changes at the CDN level, let's set up this rewrite to do
some experimentation.

frontend/next.config.js

@@ -77,12 +77,20 @@ const moduleExports = {
       ];
    },
    async rewrites() {
-      return [
-         {
-            source: '/uploads/:name',
-            destination: `${strapiOrigin}/uploads/:name`,
-         },
-      ];
+      return {
+         afterFiles: [
+            {
+               source: '/uploads/:name',
+               destination: `${strapiOrigin}/uploads/:name`,
+            },
+         ],
+         fallback: [
+            {
+               source: '/:path*',
+               destination: `https://proxy.ifixit.com/:path*`,
+            },
+         ],
+      };
    },
    async redirects() {
       return [