Today as a customer if I want to configure a custom kernel in my bootc image, I can build a container image.
But if I want that custom kernel to go in the ISO image (say I require it for lighting up my storage or network at all) I have to also ensure my container image has a `.repo` file that would allow fetching my modified kernel, and ensure it wins at depsolving in the osbuild phase. This is not obvious I think.

My suggested fix here relates to https://github.com/rhinstaller/anaconda/discussions/5888 - one option is that we default to building the anaconda environment deriving from their container image as is, dynamically installing packages into it.

But one could imagine taking it this out one step and we actually support a clear and easy way to generate the anaconda-container from a custom container...this of course heavily relates to https://gitlab.com/fedora/bootc/osbuild-cfg or some equivalent but it could in theory be

```
FROM quay.io/example/customerimage:latest
RUN dnf -y install anaconda-live-environment && dnf clean all
```

perhaps.

Anyways this bug is not about designing the solution really, but I'm mentioning my thoughts on solutions as a way to explain the problem better.