add presentation/demo about python udf

Author: jovezhong

docs/py-udf.md

@@ -2,6 +2,9 @@
 
 In addition to [Remote UDF](/remote-udf) and [JavaScript UDF](/js-udf), starting from [v2.7](/enterprise-v2.7), Timeplus Enterprise also supports Python-based UDF, as a feature in technical preview. You can develop User-defined scalar functions (UDFs) or User-defined aggregate functions (UDAFs) with the embedded Python 3.10 runtime in Timeplus core engine. No need to deploy extra server/service for the UDF.
 
+For visual learners, please watch the following video:
+<iframe width="560" height="315" src="https://www.youtube.com/embed/dizrvby2j_A?si=gZfJvv3IxRcYeMgp" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
 ## Why Python UDF
 Python is recognized as one of the most popular languages in the field of data science. Its flexibility as a scripting language, ease of use, and extensive range of statistical libraries make it an indispensable tool for data scientists and analysts.
 

docs/tutorial-python-udf.md

@@ -0,0 +1,8 @@
+# Python UDF for Real-Time Machine Learning
+
+SQL and Python are two of the most widely used tools in the data domain, both have their strengths and weaknesses, and understanding when to use each can help maximize efficiency and performance in data analysis, machine learning, and data transformation tasks.
+
+Timeplus is a unified streaming SQL platform designed for high performance and efficiency, all within a single binary. Its primary interface is SQL, which comes with inherent limitations, as mentioned earlier. To address these constraints, Timeplus has recently introduced a new feature: Python user-defined functions (UDFs). With Python UDFs, users can seamlessly integrate Python functions into SQL queries, bridging the gap between SQL and Python. This enhancement enables developers and data engineers to leverage the strengths of both languages within a single platform, unlocking greater flexibility and capability.
+
+Please read [the blog post](https://www.timeplus.com/post/python-udf) for more details, or watch the demo video on YouTube.
+<iframe width="560" height="315" src="https://www.youtube.com/embed/dizrvby2j_A?si=gZfJvv3IxRcYeMgp" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>

sidebars.js

@@ -256,6 +256,7 @@ const sidebars = {
           ],
         },
         "tutorial-sql-join",
+        "tutorial-python-udf",
         "sql-pattern-topn",
         "usecases",
         "tutorial-kv",