Refactor(build-clan): rename to lib/modules

This is a preparation for moving everything into clan, to make it all one module evaluation

lib/modules/templates/interface.nix

@@ -0,0 +1,57 @@
+{
+  lib,
+  ...
+}:
+let
+  inherit (lib) types;
+
+  templateType = types.submodule (
+    { name, ... }:
+    {
+      options.description = lib.mkOption {
+        type = types.str;
+        default = name;
+        description = ''
+          The name of the template.
+        '';
+      };
+
+      options.path = lib.mkOption {
+        type = types.path;
+        description = ''
+          Holds the path to the clan template.
+        '';
+      };
+    }
+  );
+in
+{
+  options = {
+    # clan.templates.clan
+    clan = lib.mkOption {
+      type = types.attrsOf templateType;
+      default = { };
+      description = ''
+        Holds the different clan templates.
+      '';
+    };
+
+    # clan.templates.disko
+    disko = lib.mkOption {
+      type = types.attrsOf templateType;
+      default = { };
+      description = ''
+        Holds different disko templates.
+      '';
+    };
+
+    # clan.templates.machine
+    machine = lib.mkOption {
+      type = types.attrsOf templateType;
+      default = { };
+      description = ''
+        Holds the different machine templates.
+      '';
+    };
+  };
+}