feat: elm template init

templates/elm/parts/default.nix

@@ -0,0 +1,13 @@
+{
+  perSystem = {
+    pkgs,
+    lib,
+    config,
+    self',
+    ...
+  }: {
+    imports = [
+      ./devshells.nix
+    ];
+  };
+}

templates/elm/parts/devshells.nix

@@ -0,0 +1,23 @@
+{pkgs, ...}: {
+  devShells = {
+    default = pkgs.mkShell {
+      packages = builtins.attrValues {
+        inherit
+          (pkgs)
+          alejandra
+          just
+          nil
+          ;
+        inherit
+          (pkgs.elmPackages)
+          elm
+          elm-format
+          elm-land
+          elm-language-server
+          elm-review
+          elm-test
+          ;
+      };
+    };
+  };
+}