Fall back to non-UTF8 string functions with pre-23.8 ClickHouse

[slvrtrn]

Summary

Resolves #224.

• Long changeset due to tests being moved around, split and marked as parallel to speed up the execution (up to 4x on my machine, ~1.5x on CI; that's for ClickHouse driver tests only, obviously).
• If introspected ClickHouse version is lower than 23.8, the driver will not use startsWithUTF8 and fall back to its non-UTF8 counterpart instead. There is a drawback in this compatibility mode: potentially incorrect filtering results when working with non-latin strings. If your use case includes filtering by columns with such strings and you experience these issues, consider upgrading your ClickHouse server to 23.8+.
• Added CI with ClickHouse 23.3 (current "LTS") to run at least ClickHouse driver tests. All Metabase tests will be run as usual using the latest version.

Checklist

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG