Create usePolling custom hook

ui/src/hooks/index.tsx

@@ -0,0 +1,11 @@
+import { useEffect } from "react";
+
+// usePolling repeatedly calls doFn with a fix time delay specified
+// by interval (in millisecond).
+export function usePolling(doFn: () => void, interval: number) {
+  useEffect(() => {
+    doFn();
+    const id = setInterval(doFn, interval * 1000);
+    return () => clearInterval(id);
+  }, [interval, doFn]);
+}