[MM-14058] Add support for i18n (#2190)

* Add language files

* Add react-intl, mmjstool, setup for adding translations

* Translated main module

* Translations for renderer

* A few minor fixes

* More fixes

* Add CI, add missing menu translations, other cleanup

* Added setting to manually select the language of the app

* Force English for E2e

* Unit tests

* Fix mmjstool

* Move set language to before update menu

* PR feedback

src/main/app/initialize.ts

@@ -47,6 +47,7 @@ import {setupBadge} from 'main/badge';
 import CertificateManager from 'main/certificateManager';
 import {updatePaths} from 'main/constants';
 import CriticalErrorHandler from 'main/CriticalErrorHandler';
+import i18nManager, {localizeMessage} from 'main/i18nManager';
 import {displayDownloadCompleted} from 'main/notifications';
 import parseArgs from 'main/ParseArgs';
 import TrustedOriginsStore from 'main/trustedOrigins';
@@ -359,7 +360,7 @@ function initializeAfterAppReady() {
         const filters = [];
         if (fileElements.length > 1) {
             filters.push({
-                name: 'All files',
+                name: localizeMessage('main.app.initialize.downloadBox.allFiles', 'All files'),
                 extensions: ['*'],
             });
         }
@@ -376,6 +377,14 @@ function initializeAfterAppReady() {
         });
     });
 
+    // needs to be done after app ready
+    // must be done before update menu
+    if (Config.appLanguage) {
+        i18nManager.setLocale(Config.appLanguage);
+    } else if (!i18nManager.setLocale(app.getLocale())) {
+        i18nManager.setLocale(app.getLocaleCountryCode());
+    }
+
     handleUpdateMenuEvent();
 
     ipcMain.emit('update-dict');