[$] Supporting unified kernel images for Fedora

The Fedora community is currently discussing a proposal to start supportinga unifiedkernel image (UKI) for the distribution; these images would combineseveral pieces that are generally separate today (e.g. initrd, kernel, andkernelcommand line). There are a number ofadvantages to such a kernel image, at least for some kinds of systems, butthere is worry from some about where the endpoint of this work lies. Thereis a need to ensure that Fedora can still boot non-unified, perhaps locally built,kernels and can support other use cases that unification might preclude.