testsys: Add test type for cluster templating

[ecpullen]

Issue number:

Closes #N/A

Description of changes:

Adds 2 additional fields for templating cluster config files. This allows us to provision separate clusters for each test type.

apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig
metadata:
  name: "{{kube-arch}}-{{kube-variant}}-ipv6-{{test-flavor}}"
  version: "{{version}}"
  region: "us-west-2"
kubernetesNetworkConfig:
  ipFamily: IPv6

Testing done:

TBA

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[arnaldo2792]

Folks might be already familiar with how this change affects testsys, but it will be nice to add a line or two on the PR description to help reviewers understand why this is needed or how this will improve the testsys experience.

[arnaldo2792]

Comment should reflect the change