Additional options when copying data from one year to another

[simonwep]

Discussed in #78

^{Originally posted by PiotrEsse January 22, 2025}
Hi, I think it would be better to improve copying and pasting across years. Now you copy and paste whole year.
2 improvements:

1. copy and paste just income or expenses. Not both. its more flexible
2. copy and paste - adds data not replace (selectable as a option)