feat(holiday-settings): implement organization holiday settings management

- Added SQL migration for creating organization holiday settings and state holidays tables with necessary constraints and indexes.
- Implemented API endpoints in AdminCenterController for retrieving and updating organization holiday settings.
- Updated admin-center API router to include routes for holiday settings management.
- Enhanced localization files to support new holiday settings UI elements in multiple languages.
- Improved holiday calendar component to display working days and integrate holiday settings.

worklenz-frontend/public/locales/zh/admin-center/settings.json

@@ -13,5 +13,21 @@
   "sunday": "星期日",
   "saveButton": "保存",
   "saved": "设置保存成功",
-  "errorSaving": "保存设置时出错"
+  "errorSaving": "保存设置时出错",
+  "holidaySettings": "假期设置",
+  "country": "国家",
+  "countryRequired": "请选择一个国家",
+  "selectCountry": "选择国家",
+  "state": "州/省",
+  "selectState": "选择州/省（可选）",
+  "autoSyncHolidays": "自动同步官方假期",
+  "saveHolidaySettings": "保存假期设置",
+  "holidaySettingsSaved": "假期设置保存成功",
+  "errorSavingHolidaySettings": "保存假期设置时出错",
+  "addCustomHoliday": "添加自定义假期",
+  "officialHolidaysFrom": "官方假期来自",
+  "workingDay": "工作日",
+  "holiday": "假期",
+  "today": "今天",
+  "cannotEditOfficialHoliday": "无法编辑官方假期"
 }