Initial ksonnet package for Pachyderm.

* Packages were created based on the helm chart
https://github.com/kubernetes/charts/tree/master/stable/pachyderm/templates

* Instructions for adding new packages is being added in kubeflow#609.

* I've confirmed that the resulting components can successfully be deployed
  but I don't know if Pachyderm is working yet.

* We most likely need to expose more options e.g. to control things
  like GCS bucket.

* Related to kubeflow#151