enable zramSwap on services host

hosts/services/configuration.nix

@@ -28,6 +28,12 @@
 
   nix.gc.dates = "14d";
 
+  zramSwap = {
+    enable = true;
+    memoryPercent = 1000;
+    memoryMax = 8 * 1024 * 1024 * 1024;
+  };
+
   system.stateVersion = "21.03"; # Did you read the comment?
 }