Support for local development through LocalStack

[veqryn]

I use Localstack for local development.
It has support for Athena: https://docs.localstack.cloud/user-guide/aws/athena/

Unfortunately, when I try to use athenadriver with it, the driver is trying to talk to AWS instead of my local localstack endpoint.

There needs to be a way to point athenadriver at other providers and endpoints.

This issue is related to: #47