[Walkthrough] device.xml for local_manifests

@aibd Thank you!

Wouldn’t this in itself be a good thing, to put this on github/gitlab?

In a way inspired by @piero I just built my first ROM ever, using /e docker.

Just like testing ROMs, to help development, I feel we should also use the same build-tools the dev-team is using. Plus, having a git repo with sort of stable device-manifests, would be a great starting point.

With cloning manifests, or using some dev-manifests, we could then slowly venture of into development, using /e docker as the common base build environment.

I never thought I could build /e on first try, especially on such old hardware: