[SPARK-3660][STREAMING] Initial RDD for updateStateByKey transformation

SPARK-3660 : Initial RDD for updateStateByKey transformation

I have added a sample StatefulNetworkWordCountWithInitial inspired by StatefulNetworkWordCount.

Please let me know if any changes are required.
Incorrect indentation
```
 private def convertUpdateStateFunctionWithIterator[S](
      in: JFunction2[JList[V], Optional[S], Optional[S]]   // 4 space indent
    ):  (Iterator[(K, Seq[V], Option[S])]) => Iterator[(K, S)] = {   // 2 space indent
```