Add base system flake and configuration

Signed-off-by: George Kaklamanos <gkaklas@gkaklas.gr>

nixos/configuration.nix

@@ -0,0 +1,79 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: {
+  imports = [
+    ./hardware-configuration.nix
+
+    "${builtins.fetchTarball {
+      url = "https://github.com/nix-community/disko/archive/refs/tags/v1.5.0.tar.gz";
+      sha256 = "sha256:1d03a0wb710by1m2c3rx758vy67f8r71gnv2h3qn4jj1bx10sdg4";
+    }}/module.nix"
+    ./disko.nix
+  ];
+
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+
+  networking.hostName = "kelly";
+  networking.networkmanager.enable = true;
+  time.timeZone = "Europe/Athens";
+
+  system.copySystemConfiguration = false;
+  system.stateVersion = "23.11";
+
+  programs.fish.enable = true;
+  users.users.gkaklas = {
+    isNormalUser = true;
+    extraGroups = ["wheel" "uinput"];
+    shell = pkgs.fish;
+  };
+  users.users.gkaklas.openssh.authorizedKeys.keys = [
+    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHRvzNjXbCJ1/lIcZXdJSzkadYOIoAzZ2G2stoxZY7qz gkaklas@onyx"
+  ];
+  #users.groups.uinput = {};
+  security.sudo.wheelNeedsPassword = false;
+  security.pam.services.gkaklas.kwallet.enable = true;
+
+  services.xserver.enable = true;
+  services.desktopManager.plasma6.enable = true;
+  services.displayManager = {
+    sddm.enable = true;
+    sddm.autoLogin.relogin = true;
+    autoLogin.enable = true;
+    autoLogin.user = "gkaklas";
+    defaultSession = "plasma";
+    sddm.wayland.enable = true;
+  };
+
+  services = {
+    openssh.enable = true;
+    openssh.settings.PasswordAuthentication = false;
+
+    pipewire.enable = true;
+    pipewire.pulse.enable = true;
+
+    flatpak.enable = true;
+    fprintd.enable = true;
+    fwupd.enable = true;
+  };
+
+  hardware = {
+    bluetooth.enable = true;
+    sensor.iio.enable = true;
+  };
+
+  powerManagement.enable = true;
+  xdg.portal.enable = true;
+
+  virtualisation.podman.enable = true;
+
+  nix = {
+    package = pkgs.nixFlakes;
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+  };
+}