osmscout-server: add module

Osmscout-server includes a setting in its UI to create a systemd user
service and socket to run the server on demand. This does not function
correctly on NixOS, for two reasons:

1. It assumes that the binary path is stable (e.g.
   /usr/bin/osmscout-server), which is not the case on NixOS.

2. It auto-detects the unwrapped binary path, which doesn't work.

This module allows the user to access the same functionality on NixOS.

modules/misc/news.nix

@@ -1348,6 +1348,14 @@ in
           A new module is available: 'programs.gradle'.
         '';
       }
+
+      {
+        time = "2023-12-28T08:28:26+00:00";
+        condition = hostPlatform.isLinux;
+        message = ''
+          A new module is available: 'services.osmscout-server'.
+        '';
+      }
     ];
   };
 }