feat(i18n): add French language support and enhance localization

- Introduced French as a supported language across the application, updating locale files and adding translations for various components.
- Enhanced language handling logic to accommodate French, ensuring proper detection and fallback mechanisms.
- Updated UI elements to include French language options, improving accessibility for French-speaking users.
- Refactored SEO handling to include French in hreflang links, enhancing search engine indexing for multilingual content.
- Added new scripts for managing French translations and ensuring consistency across language files.

backend/services/authService.js

@@ -144,7 +144,7 @@ export const loginUser = async ({ username, password }) => {
     const mappedParams = params.map(param => {
         return { 'name': param.paramType.description, 'value': param.value };
     });
-    const uiLocaleCodes = ['de', 'en', 'ceb', 'es'];
+    const uiLocaleCodes = ['de', 'en', 'ceb', 'es', 'fr'];
     const langEntry = mappedParams.find((p) => p.name === 'language');
     if (langEntry?.value && !uiLocaleCodes.includes(langEntry.value)) {
         const idNum = parseInt(langEntry.value, 10);