feat: moved LLMConfigs from User to SearchSpaces

- RBAC soon??
- Updated various services and routes to handle search space-specific LLM preferences.
- Modified frontend components to pass search space ID for LLM configuration management.
- Removed onboarding page and settings page as part of the refactor.

surfsense_backend/app/tasks/podcast_tasks.py

@@ -98,6 +98,7 @@ async def generate_chat_podcast(
             "configurable": {
                 "podcast_title": "SurfSense",
                 "user_id": str(user_id),
+                "search_space_id": search_space_id,
             }
         }
         # Initialize state with database session and streaming service