Add s3 command line args

[jfantinhardesty]

What type of Pull Request is this? (check all applicable)

• [x] Refactor
• [ ] Feature
• [x] Bug Fix
• [ ] Optimization
• [ ] Documentation Update

Describe your changes in brief

Currently, using the AWS_REGION environment variable was not supported and would not work correctly. This refactors the endpoint resolution and allows the AWS_REGION flag to be used. Additionally, this adds endpoint, region, and bucket-name to be passed in as command line parameters.

Checklist

• [x] Tested locally
• [ ] Added new dependencies
• [ ] Updated documentation
• [ ] Added tests

Related Issues

• Related Issue #
• Closes #