Document missing filters on the Accounts API

List business accounts now documents the iban filter, and list transactions now documents the creditDebitIndicator, processedAfter and processedBefore filters. These already worked but weren't documented. Also clarifies that from can't be combined with processedAfter or processedBefore, adds the rewards-payout transaction type, fixes the example IBANs and BIC on business account and transaction objects, which didn't pass checksum or length validation, and replaces an example that incorrectly showed a credit iDEAL payment, which can't occur.