add support for logically bound images for anaconda ISO

[cgwalters]

We landed support for logically bound images to bootc; this transparently works when generating a qcow2 today with bib because we leverage bootc install to-filesystem. However, it doesn't transparently work with the Anaconda ISO because bib doesn't know how to inject these extra images into the lookaside cache on the ISO.

This also strongly relates to rhinstaller/anaconda#5197 where Anaconda itself would learn to use bootc install to-filesystem.

Connecting these threads, I think it would make sense actually to switch to using containers-storage: (unpacked representation, as opposed to dir for both the bootc image in the ISO and all LBIs).

[ondrejbudai]

Seems like the anaconda's side got unblocked by bootc-dev/bootc#915. Basically: ostree-rs-ext is now merged inside bootc, and since bootc-dev/bootc#915, ostree container image deploy (which anaconda uses) goes through the bootc code path, so LBIs just automagically work without needing to adjust anaconda.

So we need:

• include containers-storage instead of dir inside the ISO.
• copy there LBIs in addition to the bootc image. They can be enumerated using bootc image list --type logical --format json.

[cgwalters]

copy there LBIs in addition to the bootc image. They can be enumerated using bootc image list --type logical --format json.

Yeah, though at the moment that is an experimental API. I think we can stabilize it...but maybe the more stable way to do this is to just follow the links in /usr/lib/bootc/bound-images.d and parse the quadlets.

Alternatively...what I actually like more than that is we add bootc install copy-to containers-storage:/path/to/storage or so that automatically handles this, then all that needs to be done in BIB or other disk tools is to just run that and all the images would appear in that c/storage instance.