Common footer for all files

Each file includes a footer section with the following data points (one row per item):

Title	Description
`SETTLEMENT_DATE`*	The date (`YYYY-MM-DD`) that PPRO submits funds settlement to client bank accounts
`RECORD_COUNT`	The number of transactions in the file (currency-independent)
`CHECKSUM_AGGREGATE_AMOUNT`	The sum of the transaction/refund/chargeback amount in the file (currency-independent)

*Non-European payment methods: due to non-TARGET2 business calendars or LPM specifics, some exceptions may apply. Consult PPRO’s product or integration managers for details.