Add Support for aws_credentials

[aleDsz]

Files:

config/credentials

[default]
aws_access_key_id = <aws_access_key_id>
aws_secret_access_key = <aws_secret_access_key>

config/config

[default]
region = us-east-1

config/credentials_with_token (with aws sts get-session-token)

[default]
aws_access_key_id = <session_aws_access_key_id>
aws_secret_access_key = <session_aws_secret_access_key>
aws_session_token = <aws_session_token>

[josevalim]

Once tests pass, ship it!