Migrate to nix-fast-build and update inputs

nixos-modules/virtualisation/default.nix

@@ -0,0 +1,18 @@
+{ ... }:
+{
+  virtualisation = {
+    # TODO: This should probably be somewhere else.
+    docker = {
+      enable = true;
+      enableOnBoot = false;
+    };
+    libvirtd.enable = true;
+    spiceUSBRedirection.enable = true;
+  };
+
+  boot.extraModprobeConfig = ''
+    options kvm_intel nested=1
+    options kvm_intel emulate_invalid_guest_state=0
+    options kvm ignore_msrs=1
+  '';
+}