nixos/home-assistant: allow arbitrary yaml functions

nixos/modules/services/misc/home-assistant.nix

@@ -11,9 +11,9 @@ let
     (recursiveUpdate defaultConfig cfg.config) else cfg.config));
   configFile = pkgs.runCommand "configuration.yaml" { preferLocalBuild = true; } ''
     ${pkgs.remarshal}/bin/json2yaml -i ${configJSON} -o $out
-    # Hack to support secrets, that are encoded as custom yaml objects,
-    # https://www.home-assistant.io/docs/configuration/secrets/
-    sed -i -e "s/'\!secret \(.*\)'/\!secret \1/" $out
+    # Hack to support custom yaml objects,
+    # i.e. secrets: https://www.home-assistant.io/docs/configuration/secrets/
+    sed -i -e "s/'\!\([a-z_]\+\) \(.*\)'/\!\1 \2/;s/^\!\!/\!/;" $out
   '';
 
   lovelaceConfigJSON = pkgs.writeText "ui-lovelace.json"
@@ -120,7 +120,9 @@ in {
             unit_system = "metric";
             time_zone = "UTC";
           };
-          frontend = { };
+          frontend = {
+            themes = "!include_dir_merge_named themes";
+          };
           http = { };
           feedreader.urls = [ "https://nixos.org/blogs.xml" ];
         }