list bootc images to install from containers-storage

List images from container-storage that the installer can install with, UX should be similar to how Windows Setup lets you select WIMs to install from, now with OCI instead of WIM files

<img width="600" height="450" alt="Image" src="https://github.com/user-attachments/assets/6eabf732-6b7d-42d1-923c-3e3a64552a1b" />