feat: migrate to nix flake

flake.nix

@@ -0,0 +1,60 @@
+{
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  inputs.home-manager = {
+    url = "github:nix-community/home-manager/master";
+    flake = false;
+  };
+
+  inputs.nur.url = "github:nix-community/NUR/master";
+
+  outputs = { self, nixpkgs, home-manager, nur }: let
+    systemModule = { hostName, hardwareConfig, config }: ({ pkgs, ... }: {
+      networking.hostName = hostName;
+
+      # Let 'nixos-version --json' know about the Git revision
+      # of this flake.
+      system.configurationRevision = nixpkgs.lib.mkIf (self ? rev) self.rev;
+
+      nix.registry.nixpkgs.flake = nixpkgs;
+
+      nixpkgs.overlays = [
+        nur.overlay
+      ];
+
+      imports = [
+        hardwareConfig
+        "${home-manager}/nixos"
+        config
+      ];
+    });
+  in {
+
+    nixosConfigurations.felix-nixos = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules =
+        [
+          nixpkgs.nixosModules.notDetected
+          (systemModule {
+            hostName = "felix-nixos";
+            hardwareConfig = ./hardware/felix-nixos.nix;
+            config = ./home-pc.nix;
+          })
+        ];
+    };
+
+    nixosConfigurations.pilot1 = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules =
+        [
+          nixpkgs.nixosModules.notDetected
+          (systemModule {
+            hostName = "pilot1";
+            hardwareConfig = ./hardware-configuration.nix; # TODO
+            config = ./work-pc.nix;
+          })
+        ];
+    };
+
+  };
+}