Add delete phase confirmation modal with localization support

- Implemented a confirmation modal for deleting phases in the Kanban board.
- Integrated localized messages for delete phase prompts in multiple languages, enhancing user experience.
- Updated KanbanGroup component to utilize the new confirmation modal for phase deletions.

worklenz-frontend/public/locales/en/kanban-board.json

@@ -18,6 +18,9 @@
   "deleteStatusTitle": "Delete Status",
   "deleteStatusContent": "Are you sure you want to delete this status? This action cannot be undone.",
 
+  "deletePhaseTitle": "Delete Phase",
+  "deletePhaseContent": "Are you sure you want to delete this phase? This action cannot be undone.",
+
   "dueDate": "Due date",
   "cancel": "Cancel",