cbuild: add systemd-resolved and dnf to the qemu base package set
Starting with F35 we need systemd-resolved to have DNS working in our generated image, otherwise resolv.conf symlinks to a non-existing stub file. We could work around this by generating our own resolv.conf but it's easier to just install the package expected by the distro.
And apparently the generated image no longer includes dnf on F35. dnf seems generally a good idea to have around on the target image, given that it's not that uncommon to add or remove packages at CI build time.
Fixes the errors in !125 (merged), cc @alatiera