codewide: Log errors' contents to facilitate debugging

[wprzytula]

Rust driver strives to have quite insightful error messages. It nests errors so that when displayed as string, a path can be imagined that shows where exactly an error was encountered.
Cpp driver uses error codes to signal user what went wrong. In practice, that limits user's insight a lot.
To prevent large information loss upon transition Rust driver nested error -> Cpp-rust-driver error code, I suggest logging error messages using warn! or error!.