Use pkgs.linuxPackages instead of linuxPackages_latest for
kernelPackages.
Enable the system firewall (networking.firewall.enable = true).
Comment out users.groups.kemp members entry.
Add jdk and gradle to environment.systemPackages.
Enable VirtualBox host and extension pack and add kemp to vboxusers.
Stop appending wind_speed_unit in weather.forecast_home value to avoid
duplicating units (the attribute already supplies the units). Also add
libwebp to the kemptop package list for WebP image support.
Rename group "libvirt" to "libvirtd".
Add diffoscope and nix-index to systemPackages.
Replace hplipWithPlugin with hplip.
Enable spice USB redirection and add pkgs.virtiofsd to
virtualisation.libvirtd.qemu.vhostUserPackages.
