add podman

hosts/forgejo-runner/podman.nix

@@ -0,0 +1,26 @@
+{ ... }:
+
+{
+  virtualisation.podman = {
+    enable = true;
+    dockerSocket.enable = true;
+    autoPrune = {
+      enable = true;
+      dates = "weekly";
+    };
+    defaultNetwork.settings = {
+      dns_enabled = true;
+      ipv6_enabled = true;
+      subnets = [
+        {
+          gateway = "10.88.0.1";
+          subnet = "10.88.0.0/16";
+        }
+        {
+          gateway = "fd10:88::1";
+          subnet = "fd10:88::/64";
+        }
+      ];
+    };
+  };
+}