Add Evidence user agent to DuckDB

[archiewood]

Feature Description

Hello! DuckDB 0.9.2 introduced a new option, custom_user_agent, that enables better customer issue diagnosis, as well as the ability to analyze cross-tool usage patterns of the data ecosystem tools connecting to MotherDuck. To add this option in NodeJS, pass the custom_user_agent option through the properties map:

var db = new duckdb.Database('md:my_database', {
    'motherduck_token': token,
    'custom_user_agent': 'INTEGRATION_NAME'
});

https://motherduck.com/docs/integrations/how-to-integrate/#user-agent-guidelines

Goal of Feature

DuckDB / MotherDuck can attribute usage from Evidence