Feature request: Support authentication when AWS environment variables are already available in the environment

[christophetd]

Using aws-vault to authenticate, it would be useful if cloudgoat could take into account the environment variables already available to authenticate to AWS rather than having to specify a profile.

$ aws sts get-caller-identity
{
    "UserId": "XXXXX:[email protected]",
    "Account": "123456789123",
    "Arn": "arn:aws:sts::123456789123:assumed-role/XXX/[email protected]"
}
$ ./cloudgoat.py create cloud_breach_s3
The create command requires the use of the --profile flag, or a default profile defined in the config.yml file (try "config profile").

[RyanJarv]

This would be a great change, this often effects me as well. Will look into changing this behavior.