Support online feature extraction and request mode in CLI

Now users can use Java/Python SDK to run SQL in request mode and finish online feature extraction. It would be great if we can integrated this in CLI with new SQL syntax so that users can do online feature extraction without leaving CLI.

Look at the existing CLI implementation and the Java/Python SDKs for request mode SQL execution and online feature extraction. Understand the new SQL syntax needed and how to integrate it into the CLI's command parsing and execution flow. The work involves modifying the CLI to support this new mode, likely in the code handling SQL commands.

Written by the indexing model from the issue text.