services: add hydra cache and allowed uri

modules/hardware/hydraCache.nix

@@ -0,0 +1,16 @@
+
+{ config, lib, pkgs, ... }:
+
+{
+  nix = {
+    settings = {
+      extra-trusted-public-keys = [
+        "hades-builder:AFdPgi6Qq/yKqc2V2imgzMikEkVEFCrDaHyAmOJ3MII="
+      ];
+      extra-trusted-substituters = [
+        "http://dmz.home.opel-online.de:3000/project/jovian/channel/latest"
+      ];
+    };
+  };
+  
+}