[next] Auth Callback + Chunking (#2139)

* feat: added new auth-callback

* fix: removed unused polyfill code

* fix: fixed missed intersection observer

* feat: enabled vendor chunks

* fix: fix some issues with chunk splitting

* fix: added intersection-observer to app polyfill

* fix: fixed test

* fix: removed lodash plugin which caused issue in prod

* chore: access_token -> accessToken

* feat: Show social login errors

* fix: lint + add test

* fix: restore width after facebook social login

config/webpackDevServer.config.ts

@@ -60,7 +60,10 @@ export default function({
     overlay: false,
     historyApiFallback: {
       disableDotRule: true,
-      rewrites: [{ from: /^\/admin/, to: "/admin.html" }],
+      rewrites: [
+        { from: /^\/admin/, to: "/admin.html" },
+        { from: /^\/embed\/auth\/callback/, to: "/auth-callback.html" },
+      ],
     },
     public: allowedHost,
     index: "embed.html",