Implement Reliable Transaction Submission

Send a transaction and see its validation response. For the implementation in this example, we have made the following decisions:

We allow the autofill function as a part of submitAndWait to fill up the account sequence, LastLedgerSequence and Fee. Payments are defined upfront, and idempotency is not needed. If the script is run a second time, duplicate payments will result.
We will rely on the submitAndWait function to get us the transaction submission result after the wait time.
Transactions will not be automatically retried. Transactions are limited to XRP-to-XRP payments and cannot "succeed" in an unexpected way.