Whenever we create a new mountpoint due to a user customization,
ensure the layout uses LVM, i.e. convert plain layouts to it, if
needed. This does not apply to rpm-ostree based systems, e.g. the
simplified installer since they will be using LUKS in 9.0.
Add "lvm2" to the build pipeline and thus generate new manifests
and image infos.
Co-Authored-By: Achilleas Koutsou <achilleas@koutsou.net>