chore: reorganize docs apps (#7228)

* reorganize docs apps

* add README

* fix directory

* add condition for old docs

www/packages/docs-ui/package.json

@@ -65,6 +65,7 @@
     "@segment/analytics-next": "^1.55.0",
     "@uidotdev/usehooks": "^2.4.1",
     "algoliasearch": "^4.20.0",
+    "copy-text-to-clipboard": "^3.2.0",
     "mermaid": "^10.9.0",
     "npm-to-yarn": "^2.1.0",
     "prism-react-renderer": "2.3.1",