AWS VPN Sign On Information
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-clientvpnendpoint.html
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-clientvpnendpoint-clientauthenticationrequest.html
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-clientvpnendpoint-federatedauthenticationrequest.html
https://aws.amazon.com/blogs/security/authenticate-aws-client-vpn-users-with-aws-single-sign-on/
