[test] extract method: split basic_provisioning
[test] finish refactoring out get_empty_state()
[test] move get_empty_environment to ci to resolve feature envy
[test] move environment state mangement to ci_base

This change splits prepare_environment into smaller methods, removes
more ci feature envy from BaseNodeTestCase, and fixes the incorrect
assumption that the dynamic environment_states always matches the
snapshots available from devops.