chore: add initial nix-kubernetes template

nix-kubernetes/coder.nix

@@ -0,0 +1,42 @@
+{...}: {
+  locals."git_repo_folder" = let
+    split_repo = ''split("/", data.coder_parameter.git_repo.value)'';
+  in ''try(element(${split_repo}, length(${split_repo}) - 1), "")'';
+
+  data = {
+    coder_external_auth."gitlab" = {
+      id = "gitlab";
+      optional = false;
+    };
+    coder_workspace."me" = {};
+  };
+
+  resource = {
+    coder_agent."coder" = {
+      arch = "\${var.arch}";
+      os = "linux";
+    };
+    coder_script."git_clone" = {
+      agent_id = "\${coder_agent.coder.id}";
+      display_name = "Git Clone";
+      icon = "/icon/git.svg";
+      script = let
+        repo = ''''${data.coder_parameter.git_repo.value}'';
+        repo_folder = ''''${local.git_repo_folder}'';
+      in ''
+        #!/usr/bin/env bash
+        set -eux
+
+        echo "Cloning repo \"${repo}\" if it does not exist"
+        mkdir -p ~/repos
+        pushd ~/repos
+          if [[ ! -z "${repo}" && ! -d "${repo_folder}" ]] then
+            git clone ${repo} ${repo_folder}
+          fi
+        popd
+      '';
+      run_on_start = true;
+      start_blocks_login = true;
+    };
+  };
+}