Draft: YUMI-16: Upstream release v1.0.18

Closes #2 (closed) for xenial, see !8 (merged) for focal counterpart.

@mariogrip do we still want to convert this also to a quilt style package for xenial or shall we leave it with this simple merge on top, or perhaps rebase instead and force-push to ubports/xenial once it's ready to go?