Use "standalone" output to build Next.js as a standalone app when being built e.g. in Docker. (#15405)

Co-authored-by: Jack W <jackweatherilt@outlook.com>

apps/web/next.config.js

@@ -158,6 +158,7 @@ const matcherConfigUserTypeEmbedRoute = {
 
 /** @type {import("next").NextConfig} */
 const nextConfig = {
+  output: "standalone",
   experimental: {
     // externalize server-side node_modules with size > 1mb, to improve dev mode performance/RAM usage
     serverComponentsExternalPackages: ["next-i18next"],