chore: add vercel rewrites for mintlify docs

Author: RostiMelk

vercel.json

@@ -0,0 +1,12 @@
+{
+  "rewrites": [
+    {
+      "source": "/docs",
+      "destination": "https://sanity.mintlify.dev/docs"
+    },
+    {
+      "source": "/docs/:match*",
+      "destination": "https://sanity.mintlify.dev/docs/:match*"
+    }
+  ]
+}