Support different languages inside send input

[RiccardoM]

Currently when sending some DSM to another user, the only language that is supported inside the amount input is the English one. Unfortunately, this makes it impossible to send non-round amounts (eg. 0.5 DSM) to another user if the device is set to use a different language that uses a different decimal separator from . (eg. Italian uses ,).

To fix this, we should support the input of non-round amounts even in other languages so that the decimal separator does not have to be only ..