Automatic override of AWS_REGION config

[mastrolinux]

The lines: https://github.com/encrypted-dev/userbase/blob/master/src/userbase-server/setup.js#L378 are ignoring any kind of proper setup of the region as per https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/setting-region.html

Even if running on EC2 we should allow the users to pick another region as per their config.