Currency removal

[MLZ91]

I am using the currency picker not only for picking the currency but also for all the helpful information about the currencies in currencies.dart.

By removing former currencies from currencies.dart, like the croatian kuna, I cant display former usages properly.

Proposal: Mark former currencies as removed and dont show them in the currency picker but leave them in currencies.dart (as long as the currency code isnt needed).

[Daniel-Ioannou]

Thank you for sharing your use case and the proposal regarding the management of former currencies. It's an interesting idea, and I appreciate your input.

Unfortunately, I don't have the time at this period and won't be able to address this immediately. I will implement it when time permits. However, if you're interested and would like to contribute, please feel free to fork the repository, make the necessary changes, and submit a pull request. I'd be more than happy to review and merge any pull requests, whether from you or others, for this feature.

Thank you for your understanding and potential contribution.