Add the ability to run actions right after connecting to the database

[hayssams]

You can run arbitrary SQL commands right after connecting by passing a list of SQL commands to the pre_actions parameter in connect_args

from sqlalchemy import create_engine
create_engine(
    'duckdb:///:memory:',
    connect_args={
        'pre_actions': [
            "ATTACH 'file.db' AS file_db';",
            "SET some_config_option='some_value';"
        ]
    }
)

[tiboun]

This would be a really useful addition — being able to run SQL commands on connection opening makes it much easier to set consistent session parameters across connections.

Would love to see this reviewed and merged when possible 🙌