* Added Persistent Workload guide using Host Volumes

* Update website/source/guides/stateful-workloads/stateful-workloads.html.md
Co-Authored-By: Danielle <dani@hashicorp.com>

* fix client config and job spec formatting

* fix typo in description

* fix navigation for both stateful workloads guides

* show output from nomad node status to verify host volumes

* Add value prop info; info about HA

From feedback, added more information about the value proposition for
host volumes (h/t @rkettelerij), and corrected an orphaned bit from
the original guide this one was created from.