Fixed SG per VPC creation and SSH keypair error on ec2

[retpolanne]

This PR fixes:

• Lack of iterator for subnet facts when creating a security group, introduced by Adds vpc_id to ec2_group, from subnet facts, and allows to specify SG ip cidr #2405
• Dict breaking when check if a public key existed, introduced by Added support for internal CIDR #2389

[ssbarnea]

This came too late to be merged as we already removed ec2 from core. You will have to raise it against its new location https://github.com/pycontribs/molecule-ec2/ -- but wait few days so we add the plugin code there.