[P3] Fix consistency of AWS environment variables

[willroberts]

Summary

We currently use AWS_ACCESS_KEY and AWS_SECRET_KEY in Gulp, but we use AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY in Config. We should sync these up for consistency. The easiest change would be to use the first set of values, since those are used in documentation as well.

Impacted services

• [ ] The frontend app
• [ ] The game servers
• [x] Game builds or automation scripts
• [ ] Tests or Github Actions
• [x] Infrastructure (Terraform)