chore(e2e): aws_ssh_keypair module - generate unique ssh key in terraform

[wongtonyb]

Description

https://hashicorp.atlassian.net/browse/ICU-17258

The purpose of this PR is to remove the need of enos variable aws_ssh_keypair_name for building enos scenarios. Currently it is using a locally created/stored ssh key from where the scenario is launched.

This PR creates a new enos terraform module aws_ssh_keypair. This module creates a unique ssh key, and stores it in the enos tmp folder. This module needs to be executed in the beginning of most enos scenarios; the key name, key path, and key will then be passed to resource modules in the scenario that requires it.

module.aws_ssh_keypair has 3 outputs

• key_pair_name
• private_key_path
• private_key_pem

key_pair_name & private_key_pem passed into most resource modules. most of those modules requires the private_key_pem for transport blocks.

private_key_path needed for output in test_e2e module

PCI review checklist

• I have documented a clear reason for, and description of, the change I am making.
• If applicable, I've documented a plan to revert these changes if they require more than reverting the pull request.
• If applicable, I've documented the impact of any changes to security controls.
  Examples of changes to security controls include using new access control methods, adding or removing logging pipelines, etc.