Create language model on the nim side

[osmaczko]

Description

Currently, the language model is created in LanguageStore.qml. Instead, it should be made by the backend: https://github.com/status-im/status-desktop/pull/5853#pullrequestreview-981841672

Motivation

Target languages are driven by the Lokalise platform now. The app should be able to auto-adapt to added/removed target languages or the adaptation should require as least code as possible.

Acceptance criteria

• language model is created on nim side
  • (if possible) language model is created programmatically by scanning qml_*.qm files
• bugprone imperative code initializeLanguageModel is removed

[caybro]

@osmaczko this is somewhat wrong; only Qt (and QTranslator) knows about the available UI languages, and you can query such list with Qt.locale().uiLanguages (see https://doc.qt.io/qt-5/qml-qtqml-locale.html#uiLanguages-prop). No need to build the model; scanning *.ts files would be equally wrong, you want the *.qm files, and those better be bundled in the qrc resource file when compiling.

[osmaczko]

@osmaczko this is somewhat wrong; only Qt (and QTranslator) knows about the available UI languages, and you can query such list with Qt.locale().uiLanguages (see https://doc.qt.io/qt-5/qml-qtqml-locale.html#uiLanguages-prop). No need to build the model; scanning *.ts files would be equally wrong, you want the *.qm files, and those better be bundled in the qrc resource file when compiling.

We still need to build the model, because we need other properties.

EDIT: I agree that scanning/listing *.ts files can be simplified to QLocale::uiLanguages() thanks to https://doc.qt.io/qt-6/qtranslator.html#load (description updated) We still need to scan *.qm files because QLocale::uiLanguages() only returns system langauges.

[osmaczko]

blocked by: https://github.com/status-im/status-desktop/issues/6500