[1.6.2] Add support for entering amounts with a comma / decimal seperator instead of just the numbers

Currently, amounts can only be entered by entering the entire number and the decimal point is set automatically (e.g. for 10.50 the user enters 1050). However, some users would like to be able to enter the amount directly with a comma / decimal seperator (i.e. 10.50 / 10,50 is then also entered in the app as 10.50 / 10,50 depending on the region).

This could either be implemented so that it works out of the box or, alternatively, must first be activated with another advanced setting.