For a given query execution, allow data to be returned in columnar format and deserialized to numpy objects

[paxcodes]

This PR will allow SQL query results to be returned in columns and to be deserialized to numpy objects, without affecting other queries that could run in the system (e.g. Database introspection queries, INSERT queries, etc.)

Relates:

• Allow to set columnar=True attribute when using the DB API and deserialize results into numpy objects #119

[paxcodes]

The tests are failing due to an issue in the pipeline configuration:

[paxw-panevo]

@jayvynl This is ready for review. Although it's failing on the latest clickhouse image, I've verified that it's passing on 24.10 (the version currently deployed in ClickHouse Cloud) / python 3.9.

My suspicion is that the latest ClickHouse image has a bug (it generated a password for the default user when it shouldn't have) or a backwards-incompatible change (it started requiring a password for the default user).

I already have some tests created. I'll continue to improve the test coverage after you approve the overall implementation.

[paxcodes]

Tests created in this PR are passing and not skipped when I run locally:

[jayvynl]

Although I think use_numpy and columnar should be implemented as features in clickhouse_driver like Cursor.set_settings. But I will accept your PR becase I think this may help others.

Please update the tox.ini file to add numpy and pandas

commands =
    pip install pandas
    # Use local clickhouse_backend package so that coverage works properly.
    pip install -e .
    coverage run tests/runtests.py --debug-sql {posargs}

Please update document and changelog.

[paxcodes]

@jayvynl The changes have been made:

• tox.ini has been modified and pandas has been installed
• changelog entry and documentation has been added

The checks look good now, aside from running tests against the latest clickhouse image, for the same reason mentioned before.

I wonder whether it'd be valuable to add the clickhouse version deployed in ClickHouse Cloud in the matrix. I can create PRs in the future to make sure the CI/CD pipeline config is updated whenever ClickHouse Cloud has deployed new ClickHouse versions.