Align MT940 parser with other parsers

[michielbdejong]

The ing-creditcard-scrape parsers returns an array of objects

{
      from: 'ING Creditcard',
      to: 'Counterparty',
      date: obj.date,
      amount: -parseFloat(obj.amount),
      unit: 'EUR',
      halfTradeId: `ing-bank-cc-${obj.date}-${uuidV4()}`,
      description: obj.description
}

and similar for ingbank-csv, paypal-csv, and wiebetaaltwat. But the mt940 parser is tied into run.js and effectively only outputs the month, expenseCategory, amount variable that are used in https://github.com/solid/money-pane/blob/96ae9575ab5efe691e98561916d488c9db34446b/run.js#L134.