Authentication functionality for CDAP on Kubernetes setup

Currently CDAP has Authentication feature for Standalone and Distributed deployments.

Up until now there was no such functionality in CDAP running on Kubernetes.

This feature is about bringing this capability in so that all deployments have Authentication feature available for the users.

Design document: https://wiki.cask.co/display/CE/Authentication+feature+for+CDAP+on+Kubernetes+deployment