This, in turn, causes the kernel to go to console level 4. Not ideal
when a user tries to set it to something else. Leave this to
boot.consoleLogLevel.
For the time being, this is mostly a copy of the QEMU system.
The QEMU system is slated to be removed, once the UEFI system provides
the necessary tooling to get a VM going easily.
We'll probably want to add other generically-useful modules to that
system.
We'll have to look at NixOS's boot.initrd.availableKernelModules and
boot.initrd.kernelModules options.