In 4.13 and earlier, MicroShift looked at /var/lib/microshift/manifests and /etc/microshift/manifests for kustomize.yaml. We want to also support looking at multiple subdirectories to support different apps being packaged independently and deployed to the host.

To ensure isolation between the new locations, we want to have a $path/subdir/kustomization.yaml file, or one kustomization.yaml per subdir.

To ensure isolation between the new locations and the existing locations, we likely want to add /var/lib/microshift/manifests.d and /etc/microshift/manifests.d as top-level directories to scan.