v2 okta-aws-cli - headless / machine to machine

[monde]

I'm working on a headless feature for okta-aws-cli. The target use case is for automation, like in a CI tool chain or other production workflows/jobs/processes that are headless.

We have a goal of EA by the beginning of October. It will make use of an Okta OAuth app with private key or client secret credential, an Okta Custom Authorization Server, and an IAM OIDC enabled IdP

• https://developer.okta.com/docs/guides/implement-oauth-for-okta-serviceapp/main/
• https://developer.okta.com/docs/guides/customize-authz-server/main/
• https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html

I'll try and address nice to have features in our GH issues as well as bug fixes in v2.

Okta internal reference: https://oktainc.atlassian.net/browse/OKTA-642709

[monde]

duplicate #115