[3.x] Adding custom language translation to the project

[rozsazoltan]

If you create a translation for your language in the form of a PR, I'd be happy to merge it into the project.

Files containing translations

• ./app/locales/{!! langCode !!}/translation.json (server application texts)
• ./app/client/public/locales/{!! langCode !!}/translation.json (client application texts)

Modifying the necessary files for translation

• In the ./app/locales/ folder, add the native name of the new language for all other languages. For example, for the Hungarian language: "hu": "Magyar".
• In the ./app/configs/i18next.config.client.ts file, add the new language. For the Hungarian language, for example:

  import translationHU from '../locales/hu/translation.json';
  
  // ...
  res.push(translationHU.Hello);

• In the ./app/configs/i18next.config.client.spec.ts file, add the new language. For the Hungarian language, for example:

  expectedMap.set('Magyar', 'hu');
  
  // ...
  expectedMap.set('Magyar', 'hu');