feat: multiple playground choices (#5207)

* poc of using netlify functions for playground redirections

* push

* cleanup

* restore files

* fix netlify functions?

* fix netlify functions?

* implement serverless functions for playgrounds with persistent cookie

* move new.docusaurus.io to monorepo packages

* move new.docusaurus.io to monorepo packages

* lockfile

* push

* catch-all redirect

* Translate/Interpolate: add better error message if not used correctly

* Add /docs/playground page

* Add some additional doc

website/sidebars.js

@@ -12,7 +12,12 @@ module.exports = {
       type: 'category',
       label: 'Getting Started',
       collapsed: false,
-      items: ['installation', 'configuration', 'typescript-support'],
+      items: [
+        'installation',
+        'configuration',
+        'playground',
+        'typescript-support',
+      ],
     },
     {
       type: 'category',