Create a script to start a new ledger file

[somecho]

At the end of the year, it's common practice to carry on this year's balance into the new financial year. The idea of this script is to have something like newledger -f lastyear.ledger -o thisyear.ledger, setting up the accounts properly.

If no input file is given, then allow key-value pairs to be given to setup the equity account. Example: newledger -o thisyear.ledger -a Assets:Cash -v '100.00 EUR' -a Liabilities:Loan -v '200.00 EUR'. Example output would be:

2024/01/01 Opening Balance
    Assets:Cash                                                100.00 EUR
    Liabilities:Loan                                           200.00 EUR
    Equity