ADD volume backup interface for students

[wabscale]

Add the ability to list, and revert to a volume backup. This will involve writing a small interface on our backend that will need to call out to longhorn things.

Reverting involves the steps:

1. deleting the existing pvc, pv and longhorn volume
2. selecting and restoring the longhorn backup
3. recreate the pv and pvc based off backup metadata

We'll need to have a check that IDEs are not and using that volume.

Longhorn very infuriatingly does not have a cli. It is a bit insane actually that it lacks this. It drives me insane having to click so many buttons in their stupid admin site. Thankfully they have an exposed api that we're not technically suppose to interface with, but who cares:

• https://github.com/longhorn/longhorn-ui/blob/master/src/models/backup.js
• https://github.com/longhorn/longhorn-ui/blob/master/src/services/backup.js