chore: prepare legacy site deploy (#13987)

This basically removes everything but the home page and docs/tutorial. More specifically:

- add old tutorial to nav
- strips out implementations of repl and blog, these links go to the current blog/repl instead
- removes examples
- adds deprecation banner
- link to current site

Author: dummdidumm

sites/svelte.dev/package.json

@@ -5,9 +5,9 @@
   "description": "Docs and examples for Svelte",
   "type": "module",
   "scripts": {
-    "dev": "node scripts/update.js && pnpm run generate && vite dev",
-    "build": "node scripts/update.js && pnpm run generate && vite build",
-    "generate": "node scripts/type-gen/index.js && node scripts/generate_examples.js",
+    "dev": "node scripts/update.js && vite dev",
+    "build": "node scripts/update.js && vite build",
+    "generate": "node scripts/type-gen/index.js",
     "update": "node scripts/update.js --force=true",
     "preview": "vite preview",
     "start": "node build",