use ansible_hostname for kodi nix hostname

roles/kodi-config/templates/configuration.nix.j2

@@ -15,7 +15,7 @@
   boot.loader.systemd-boot.enable = true; 
 
   # Set hostname
-  networking.hostName = "kodi-nix"; 
+  networking.hostName = "{{ ansible_hostname }}";
 
   # Set time zone.
   time.timeZone = "America/Los_Angeles";