router, pre-router: move DHCP server

hosts/router/10-net-services.nix

@@ -27,6 +27,31 @@
     };
   '';
 
+  services.kea.dhcp4 = {
+    settings = {
+      interfaces-config = {
+        interfaces = [ "net-services" ];
+      };
+      subnet4 = [
+        {
+          id = 10;
+          subnet = "10.42.10.1/24";
+          pools = [
+            {
+              pool = "10.42.10.100 - 10.42.10.240";
+            }
+          ];
+          option-data = [
+            {
+              name = "routers";
+              data = "10.42.10.1";
+            }
+          ];
+        }
+      ];
+    };
+  };
+
   # Everyone is allowed reaching this, no firewall therefore
 
   clerie.uplink-selector.interfaces.net-services.uplink = "uplink-a";