feat: Implement document saving with reindexing

- Updated the document saving endpoint to trigger reindexing after saving.
- Introduced a new Celery task for reindexing documents.
- Refactored the editor page to reflect the changes in the API endpoint and method.

surfsense_backend/app/celery_app.py

@@ -64,6 +64,7 @@ celery_app = Celery(
         "app.tasks.celery_tasks.connector_tasks",
         "app.tasks.celery_tasks.schedule_checker_task",
         "app.tasks.celery_tasks.blocknote_migration_tasks",
+        "app.tasks.celery_tasks.document_reindex_tasks",
     ],
 )