refactor: Use haumea for filesystem-based module system for flake outputs

refactor: Use hyphen(`-`) for variable names & folder names(except Python), replace all unserscore(`_`) with hyphen(`-`).

hosts/k8s/k3s-prod-1-worker-1/k3s.nix

@@ -0,0 +1,23 @@
+{
+  config,
+  pkgs,
+  myvars,
+  ...
+}: let
+  serverName = "k3s-prod-1-master-1";
+  serverIp = myvars.networking.hostAddress.${serverName}.address;
+  package = pkgs.k3s_1_29;
+in {
+  environment.systemPackages = [package];
+  services.k3s = {
+    inherit package;
+    enable = true;
+    role = "agent";
+    serverAddr = "https://${serverIp}:6443";
+    tokenFile = config.age.secrets."k3s-prod-1-token".path;
+    # https://docs.k3s.io/cli/agent
+    extraFlags =
+      " --node-label=node-type=worker"
+      + " --data-dir /var/lib/rancher/k3s";
+  };
+}