Add placeholder Plus Voting page

app/routes/plus/voting/index.tsx

@@ -0,0 +1,12 @@
+import { monthsVotingRange, upcomingVoting } from "~/core/plus";
+
+export default function PlusVotingPage() {
+  return (
+    <div className="text-sm text-center">
+      Next voting starts{" "}
+      {monthsVotingRange(upcomingVoting(new Date())).startDate.toLocaleString(
+        "en-US"
+      )}
+    </div>
+  );
+}