Start porting nixy config, move some bootloader stuff into the common bootloader.nix.

nodes/hosts/common/system/bootloader.nix

@@ -0,0 +1,10 @@
+{ pkgs, config, ... }: {
+  boot = {
+    loader = {
+      systemd-boot.enable = true;
+      efi.canTouchEfiVariables = true;
+    };
+    kernelPackages = pkgs.linuxPackages_xanmod_stable;
+  };
+}
+