[Discussion] add a CLI tool for debug and test purpose

I'm thinking of adding a CLI tool to manipulate the catalog, and potentially execute queries and update the underlying dataset, to simplify integration testing. With this tool, we could easily add new test cases by writing simple test specification files and corresponding expected output files.

Additionally, we could integrate this CLI with other Iceberg implementations (e.g., PyIceberg or Spark) to enable cross-language integration tests, which has been discussed here [1].

I haven't thought deeply yet about cross-language integration tests, but I believe adding a CLI tool for iceberg-cpp would significantly benefit our development workflow.

Thoughts?

[1] https://lists.apache.org/thread/wkfbshdngw32jdzclp9hj6flpcdtbl1l