bib: add new --partition-mode switch to enable lvm

[mvo5]

This allows us to quickly enable lvm. Draft as I think we need to decide on the UX, i.e. if this should be done via the blueprint config or commandline or both and how it interacts with --rootfs and btrfs.

This needs:
osbuild/images#876
osbuild/osbuild#1867
osbuild/osbuild#1862

but with that I was able to:

$ bootc-image-builder manifest --partition-mode lvm quay.io/centos-bootc/centos-bootc:stream9
...
$ kvm -m 1500 -cpu host disk.raw
...
localhost login: root
Password: 
[systemd]
Failed Units: 1
  bootc-generic-growpart.service
[root@localhost ~]# mount|grep "/sysroot "
/dev/mapper/rootvg-rootlv on /sysroot type xfs (ro,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota)

[cgwalters]

Failed Units: 1
  bootc-generic-growpart.service

should be fixed by https://gitlab.com/fedora/bootc/base-images/-/merge_requests/33

[github-actions]

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