Allow starting khoj in non-GUI mode without config file instantiated

- Start khoj server (in non-GUI mode) without needing config file
  already instantiated.
  - But throw warning to configure khoj to use it
- This allows plugins to configure the app via the /config/data APIs
- To be used by the Khoj obsidian plugin to configure markdown content
  in khoj

src/main.py

@@ -77,7 +77,7 @@ def run():
         # Setup task scheduler
         poll_task_scheduler()
         # Start Server
-        configure_server(args, required=True)
+        configure_server(args, required=False)
         start_server(app, host=args.host, port=args.port, socket=args.socket)
     else:
         # Setup GUI