Deprecating embedded aws-okta support

[edulop91]

Per segmentio/aws-okta#278, development and maintenance of aws-okta is halted. Because of this, chanzuckerberg/blessclient will drop support for embedded aws-okta.

You can continue using aws-okta as an auth provider by configuring your ~/.aws/config to use aws-okta using something similar to

[profile account]
region             = us-west-2
output             = json
credential_process = sh -c 'aws-okta cred-process okta-account --mfa-duo-device phone1 2> /dev/tty'

[profile okta-account]
role_arn     = arn:aws:iam::xxxxx:role/my-role
aws_saml_url = home/amazon_aws/foobar/baz

Furthermore, we are working on a replacement for aws-okta that relies on OIDC federation rather than SAML. We hope this will simplify things and reduce the burden of maintenance. More to come in the following weeks.