Full deploy/reset instructions

[eiddor]

From a discussion at: https://github.com/balenalabs/balena-sound/issues/434

Sometimes while troubleshooting issues (mine or others), I want to start with a completely fresh deployment free from any hacking/customization that I've done or leftovers from past versions. Today I end up creating an entirely new application and device for this purpose, which also involves downloading a new image, replacing SD-cards, etc.

"Purge data" sometimes gets me there, but I've noticed that anything modified on the host still persists.

Is there an easier way to start completely fresh using the same device/application without having to rebuild? If so, it would be great to have some documentation on it.

Thanks!