Add coredns module

clanServices/coredns/flake-module.nix

@@ -0,0 +1,18 @@
+{ lib, ... }:
+let
+  module = lib.modules.importApply ./default.nix { };
+in
+{
+  clan.modules = {
+    coredns = module;
+  };
+  perSystem =
+    { ... }:
+    {
+      clan.nixosTests.coredns = {
+        imports = [ ./tests/vm/default.nix ];
+
+        clan.modules."@clan/coredns" = module;
+      };
+    };
+}