Add optional verbose output

[bruceadams]

Slightly verbose would list the names of the databases found and the names of database users, along with simple counts of number of rows updated and the number of rows retrieved.

Very verbose would output the full responses from each AWS call.

These messages should go to stderr so that pipelines for the data continue to work.

[bruceadams]

This is in place (and has been for a while). It's not pretty 🤷‍.