make docker optional, fix podman dns problem

hosts/common/global/default.nix

@@ -4,7 +4,6 @@
     inputs.home-manager.nixosModules.home-manager
     ./acme.nix
     ./auto-upgrade.nix
-    ./docker.nix
     ./fish.nix
     ./locale.nix
     ./nix.nix

hosts/common/global/podman.nix

@@ -1,8 +1,9 @@
-{ lib, ... }: {
+{
   virtualisation.podman = {
     enable = true;
     dockerCompat = true;
     dockerSocket.enable = true;
+    defaultNetwork.dnsname.enable = true;
   };
 
   environment.persistence = {