Add possible to custom configure decimals

[mades]

Since currencies like Bitcoin with 8 decimal places or Ethereum with 18 decimal places exist, it would be beneficial to allow configuration of currency decimals to more than 2 diсimals places

[tiberiusteng]

Everything in the app (input form, list, report calculation etc) is more or less hard-coded for 2 decimal places, so it's unlikely I'll change them all to accommodate adjustable decimal points ...