declare rootless docker for 'andromache' host

hosts/andromache/default.nix

@@ -37,6 +37,7 @@ in
       inherit inputs;
       inherit config;
     })
+    ../../modules/docker.nix
   ];
 
   secrets.username = username;

modules/docker.nix

@@ -0,0 +1,9 @@
+{
+  virtualisation.docker = {
+    enable = false;
+    rootless = {
+      enable = true;
+      setSocketVariable = true;
+    };
+  };
+}