Add localisation support
Build a l10n system like we did in copyclient_electron, using locale files (JSON?) and some
getString(id)
function, so we can support other languages
use intl package (https://pub.dev/packages/intl) to implement translation like in aufwerter client (https://git.uni-paderborn.de/asta/aufwerter_ng)
Edited by Leon Tappe