feat(i18n): add i18n on server side

- remove the hardcoded list of locales in favor of a discovry on start time
    - server will stop on badly formatted locale .json
    - add server.* entries for serer side translation

    server side translation will be used for templating and email
    note: no json in some embded html (like in /magic), amount of work was similar

src/interfaces/api/handlers/i18n_handler.rs

@@ -51,11 +51,12 @@ impl I18nHandler {
             None => None,
         };
 
+        let resolved_locale = locale.clone().unwrap_or_default();
         match service.translate(&query.key, locale).await {
             Ok(text) => {
                 let response = TranslationResponseDto {
                     key: query.key,
-                    locale: locale.unwrap_or(Locale::default()).as_str().to_string(),
+                    locale: resolved_locale.as_str().to_string(),
                     text,
                 };
                 (StatusCode::OK, Json(response)).into_response()
@@ -75,7 +76,7 @@ impl I18nHandler {
 
                 let error = TranslationErrorDto {
                     key: query.key,
-                    locale: locale.unwrap_or(Locale::default()).as_str().to_string(),
+                    locale: resolved_locale.as_str().to_string(),
                     error: error_msg,
                 };