Add graph command

[pheinrichs]

Opening this to start discussion.

Right now the second parameter the command uses is the namespace, but has to be encapsulated by quotes. Should we switch this represent file structure rather than namespace, doing so we wouldn't need quotes for the second parameter.

---

Please see our contributing docs

• [ ] Have you created any necessary docs?
• [ ] Have you created tests for Travis integration?
• [x] Have you used localisation in the WebUI?
• [x] Have you included the proper copyright?

[mention-bot]

@pheinrichs, thanks for your PR! By analyzing the history of the files in this pull request, we identified @laf and @murrant to be potential reviewers.

[CLAassistant]

All committers have signed the CLA.