Add option to skip connection to DB for dry run

[colmsnowplow]

The latest version attempts to connect to the target on dry run. This is great, but sometimes we just want a local dry run without yet adding credentials to the playbook - to check that the playbook and sql files are all in order and in the right places.

This is slowed down significantly by attempts to connect, it would be nice to have an option for the old style dry run too.