docs: Support godoc examples for 'simple' and 'advanced' configurations, add GoDoc badge

[dxh9845]

This PR adds Godoc examples on how to use the Goduckdb driver. These examples will be rendered inline on the DuckDB GoDoc page.

Here's how the examples look when rendered locally:

I've also added the GoDoc badge that will link directly to the documentation.

Please let me know if this is ok!