nixos.users-groups: Set up subuid/subgid mappings for all normal users

This is required by (among others) Podman to run containers in rootless mode.

Other distributions such as Fedora and Ubuntu already set up these mappings.

The scheme with a start UID/GID offset starting at 100000 and increasing in 65536 increments is copied from Fedora.

nixos/modules/virtualisation/containers.nix

@@ -23,6 +23,15 @@ in
     maintainers = [] ++ lib.teams.podman.members;
   };
 
+
+  imports = [
+    (
+      lib.mkRemovedOptionModule
+      [ "virtualisation" "containers" "users" ]
+      "All users with `isNormaUser = true` set now get appropriate subuid/subgid mappings."
+    )
+  ];
+
   options.virtualisation.containers = {
 
     enable =
@@ -99,15 +108,6 @@ in
       '';
     };
 
-    users = mkOption {
-      default = [];
-      type = types.listOf types.str;
-      description = ''
-        List of users to set up subuid/subgid mappings for.
-        This is a requirement for running rootless containers.
-      '';
-    };
-
   };
 
   config = lib.mkIf cfg.enable {
@@ -122,26 +122,6 @@ in
       registries = lib.mapAttrs (n: v: { registries = v; }) cfg.registries;
     };
 
-    users.extraUsers = builtins.listToAttrs (
-      (
-        builtins.foldl' (
-          acc: user: {
-            values = acc.values ++ [
-              {
-                name = user;
-                value = {
-                  subUidRanges = [ { startUid = acc.offset; count = 65536; } ];
-                  subGidRanges = [ { startGid = acc.offset; count = 65536; } ];
-                };
-              }
-            ];
-            offset = acc.offset + 65536;
-          }
-        )
-        { values = []; offset = 100000; } (lib.unique cfg.users)
-      ).values
-    );
-
     environment.etc."containers/policy.json".source =
       if cfg.policy != {} then pkgs.writeText "policy.json" (builtins.toJSON cfg.policy)
       else copyFile "${pkgs.skopeo.src}/default-policy.json";