Implemented 'deployment' option to capture custom attributes related to the system configuration

svn path=/nixos/trunk/; revision=24848

modules/misc/deployment.nix

@@ -0,0 +1,23 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+{
+  options = {
+
+    deployment = mkOption {
+      description = ''
+        This option captures various custom attributes related to the configuration of the system, which
+        are not directly used for building a system configuration. Usually these attributes
+        are used by external tooling, such as the nixos-deploy-network tool or the Disnix Avahi
+        publisher.
+      '';
+      default = {};
+      example = {
+        description = "My production machine";
+	hostname = "my.test.org";
+	country = "NL";
+      };
+    };
+  };
+}

modules/module-list.nix

@@ -24,6 +24,7 @@
   ./installer/tools/tools.nix
   ./misc/assertions.nix
   ./misc/check-config.nix
+  ./misc/deployment.nix
   ./misc/ids.nix
   ./misc/locate.nix
   ./misc/nixpkgs.nix