Automatically create database if it doesn't exist

[rabidaudio]

With Meltano, I like to namespace each extractor to a new database to avoid conflicts (like tap-github and tap-shopify both having users tables) by setting the database name dynamically:

config:
  athena_database: $MELTANO_EXTRACTOR_NAMESPACE

However this means the database needs to exist before the tap can be run.

This change runs CREATE DATABASE IF NOT EXISTS before uploading.

Because meltano/sdk#246 hasn't been implemented, there's not a clean place to put a setup step to run once before the whole target run. Instead this will run for each sink in the constructor, which is not ideal but it should be fine.

[ndrluis]

Hello @rabidaudio Thank you for your contribution.

In our use case at Gupy we have the expectation to create the database manually, because of that I think that would be nice to have a setting to enable this feature.

What do you think about it?