Allow usage to set roles in the aws config file

[Erog38]

I was using this for some time to set my aws environment until I started to need access to many different accounts. I find myself taking too much time switching contexts and started to alter my workflow to use aws-okta as part of a kube context change. This still requires you to set the AWS ARN roles up in the config file. Since this codebase has a significant amount of code needed to make this happen, I extended it to suit my needs.

This is an issue as to also submit a PR for the changes that happened to support this functionality.

Expected Behavior

gimme-aws-creds -a 

Only writes the AWS arn role to the specified aws config file. Otherwise no functionality changes.

Current Behavior

Only set aws credentials.

Possible Solution

PR to follow

Context

Switching kube contexts for an EKS cluster requires two steps, authentication and context switching. This in conjunction with aws-okta allos authentication to happen transparently when you switch contexts.

Your Environment

• App Version used: 1.1.8
• Environment name and version: Python 3.7 from Homebrew
• Operating System and version: MacOSX