move more stuf out of flake.nix

nixosModules/pxvirt-guest.nix

@@ -0,0 +1,26 @@
+{ modulesPath, lib, ... }:
+{
+  imports = [ (modulesPath + "/virtualisation/proxmox-lxc.nix") ];
+
+  config = {
+    # TODO is this needed?
+    # nix.settings.sandbox = false;
+
+    proxmoxLXC = {
+      manageNetwork = false;
+      privileged = false;
+    };
+
+    # Let Proxmox host handle fstrim
+    services.fstrim.enable = false;
+
+    # TODO is this needed
+    # Cache DNS lookups to improve performance
+    services.resolved.extraConfig = ''
+      Cache=true
+      CacheFromLocalhost=true
+    '';
+
+    boot.loader.systemd-boot.enable = lib.mkForce false;
+  };
+}