[RFE] Create mechanisms that enable `deploy` and `destroy` commands to limit actions to downstream clusters

[git-ival]

• Create a mechanism, either via the deploy command or some other method, to limit deployments to only downstream clusters
  • Upstream and "tester" clusters should not be mandatory when using this method
• Create a mechanism, either via the destroy command or some other method, to limit teardown actions to only downstream clusters
  • Upstream and "tester" clusters should not be destroyed when using this method

Notes: Will likely need to make use of dartboard's upcoming "ClusterState" file (see #56) in order to accomplish this.