Install an Argo workflow to run Dask jobs

[jpolchlo]

This is in response to azavea/noaa-hydro-data#120. The task here is to bring the workflow provided in that PR into the cluster as a common piece of infrastructure. It should be available as a ClusterWorkflowTemplate in the daskhub namespace by default. This implies the need for a flag in application/daskhub to select for Argo-related support files, so in the event that Argo has not been installed, the template will be left out.