db-facts templates don't work well for AWS IAM credentials

[austinweisgrau]

db-facts templates work well for a variety of database credentials, but don't work well for AWS IAM credentials.

AWS IAM credentials might be out of the ideal scope for the tool, but there does exist a precedent of using the tool with IAM credentials.

Ideally, db-facts could output AWS IAM credentials with appropriate keys AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY rather than username and password

This would enable a one-liner to credential the shell environment with aws without any additional parsing, similar to how db credentials are accessed: eval $(db-facts sh credential_name)

[austinweisgrau]

Resolved with #33