chore: modify kaggle docs & Adding ds_loop at program entry (#786)

* modify kaggle docs

* optimise code based on comments

* Update docs/scens/kaggle_agent.rst

* fix docs build error

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Co-authored-by: you-n-g <you-n-g@users.noreply.github.com>

rdagent/app/cli.py

@@ -18,10 +18,10 @@ from importlib.resources import path as rpath
 import fire
 
 from rdagent.app.data_mining.model import main as med_model
+from rdagent.app.data_science.loop import main as kaggle
 from rdagent.app.general_model.general_model import (
     extract_models_and_implement as general_model,
 )
-from rdagent.app.kaggle.loop import main as kaggle_main
 from rdagent.app.qlib_rd_loop.factor import main as fin_factor
 from rdagent.app.qlib_rd_loop.factor_from_report import main as fin_factor_report
 from rdagent.app.qlib_rd_loop.model import main as fin_model
@@ -55,6 +55,6 @@ def app():
             "ui": ui,
             "health_check": health_check,
             "collect_info": collect_info,
-            "kaggle": kaggle_main,
+            "kaggle": kaggle,
         }
     )