Update Ollama configuration and add Open WebUI support

- Fix ollama module by removing invalid meta section
- Update grey-area ollama service configuration:
  - Change host binding to 0.0.0.0 for external access
  - Remove invalid rsyslog configuration
  - Enable firewall access
- Add Open WebUI module with proper configuration:
  - Integrate with Ollama API at localhost:11434
  - Disable authentication for development
  - Open firewall on port 8080
- Successful test build of grey-area configuration

machines/grey-area/configuration.nix

@@ -25,6 +25,7 @@
     ./services/audiobook.nix
     ./services/forgejo.nix
     ./services/ollama.nix
+    ../../modules/services/open-webui.nix
   ];
 
   # Swap zram