Expose `--host` for docker-compose support

If we have dynamodb-local running as a docker container and compose the services with docker-compose, we'd still like to use this package for the migrate functionality.
However, in a docker-compose scenario, dynamodb-local runs on a separate host and for this to work, this package would need to expose a `--host` option.

Is this something you'd consider exposing?

Start by finding the migrate functionality and the existing command-line option parsing. Trace how the local DynamoDB host is currently selected, then verify that a --host value can target a separate service in a docker-compose setup. Done means the option is accepted and migration requests reach the configured host.

Written by the indexing model from the issue text.