[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.
Aah, right. But actually, you can improve that too. Instead of sorting, you could convert the list-of-list to a list-of-sets, and then assert. Then the `T extends Comparable`  can be removed. Wanna try that?