Replace Playground with JSX Editor (#1500)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1500

Inspired by the frequent usage of Expo snacks to run RN, to repro Yoga issues, this replaces the Playground port with a new ground up Playground UI. This UI right now is pretty simple, with a JSX editor which creates a Yoga tree, which is then rendered using the WebAssembly variant of Yoga.

There are a lot of ways we can continue to improve this, but this merges the foundation. Subjectively, I find this more useful as a tool to play with Yoga behavior than the GUI.

This also replaces some of the bits of the homepage, and adds a playground entrypoint (though it's pretty identical to the one I've been testing on the home page).

Reviewed By: yungsters

Differential Revision: D51963201

fbshipit-source-id: 1265cb1784151b685686e189d47ecd42cbacdf8f

website-next/package.json

@@ -17,14 +17,15 @@
     "lint:fix": "eslint . --fix"
   },
   "dependencies": {
-    "@docusaurus/core": "3.0.0",
-    "@docusaurus/preset-classic": "3.0.0",
+    "@docusaurus/core": "3.0.1",
+    "@docusaurus/preset-classic": "3.0.1",
     "@mdx-js/react": "^3.0.0",
-    "clsx": "^1.2.1",
-    "immutable": "^4.0.0",
-    "prism-react-renderer": "^2.1.0",
+    "clsx": "^2.0.0",
+    "nullthrows": "^1.1.1",
+    "prism-react-renderer": "^2.3.0",
     "react": "^18.0.0",
     "react-dom": "^18.0.0",
+    "react-live": "^4.1.5",
     "yoga-layout": "0.0.0"
   },
   "devDependencies": {