Set up end to end testing of the plugin.

[rohantmp]

We're currently exploring the Cockpit Project's own test infrastructure:

https://piware.de/post/2017-12-21-phantomjs-to-chromium/
https://cockpit-project.org/blog/cockpit-starter-kit.html
https://cockpit-project.org/blog/cockpit-custom-test-framework.html

The front end stuff is supported by cockpit's testlib.py api which provisions virtual machines using their testvm.py api.

We need to see if a solution exists to provision VMs that:

• have glusterd2 setup and other dependencies setup.
• have extra disks attached.

[rohantmp]

Maybe explore testing with containers. May not need the bulk of VMs that cockpit does. Containers will make it easier to run test locally.