[Merge] ~itrue/livecd-rootfs:add-nemos-support-v5 into livecd-rootfs:ubuntu/master

[Isaac True]

arm64 (https://launchpad.net/~nemos-team/+livefs/ubuntu/lunar/nemos/+build/528300) and amd64 (https://launchpad.net/~nemos-team/+livefs/ubuntu/lunar/nemos/+build/528299) minimal images built successfully with this branch.

We're still running into this bug for the reference images: https://bugs.launchpad.net/nemos/+bug/2013339

I'll make the changes suggested by @lool when I can
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https://code.launchpad.net/~itrue/livecd-rootfs/+git/livecd-rootfs/+merge/455293
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