Produce apis to add a k8s cloud and tear down its models first

[addyess]

• pytest operator supports add_k8s() method
• tears down the clouds first, tearing down any models on those clouds first
• tears down any other models last in reverse order they are created
• allows creation of a k8s cloud given a kubernetes.client.configuration.Configuration
• supports add-k8s arguments like context, skip_storage and storage_class
• see test_opstest_add_k8s.py for example of how to use until I can get documentation into this
• uses updated inclusivity workflow check

[mateoflorido]

LGTM!